The original Dungeoneer was produced in my pre-Judges Guild days (while I was still in college).  Thanks for the compliments, btw.  You'll excuse my lack of perfect memory regarding the project; it has been over 30 years since the first issues were produced.  Issue #1 (Featuring "The Ugly" on the cover).

Mark Hendricks and I put together the first issue.  We called ourselves The Fantastic Dungeoning Society (initials F.D.S. which was, unfortunately the same as used by popular feminine hygiene spray of the day).  The inspiration for the magazine came from our observation that there really weren't any good fanzines out there specifically for our new passion of Dungeons & Dragons.  We (or at least I) thought it would also be really cool to completely work out adventures that other DMs could just run, instead of having to spend a lot of time creating them (or relying on random tables, etc.)

For that first magazine, I did all the art, wrote a good share of the articles and did the camera-ready paste-up (which if I remember was done at least at 200% of the original printed size -- a 5.5" x 8.5" (half-size) saddle-stitched magazine on white bond paper with a tan cover stock cover).  We mailed a good share of that original print run to people whose names we retrieved from similar publications.  The original press run was done at a quick-print shop (long long gone now) in downtown Jackson, Michigan in the summer of 1976.  The reprint of the first issue of the magazine has yellow cover stock and printed by Arrowswift Printing of Jackson, Michigan (whom I later worked for as a paste-up artist) because they did not use a tan cover stock.

We sent the first magazine out "blind", hoping that people would like it and subscribe.  A surprising number did.  And even with that, we got actual angry letters from people for sending it to them (apparently in those days, folks disliked D&D because it wasn't historical based gaming, not because it was destroying the youth of America).

The text for the magazine was "set" by first typing out the articles in column widths on Mark Hendrick's Smith Corona typewriter with the fancy black mylar ribbon cartridge.  Then I would go through and mark it up with a red pencil to indicate where additional spaces would be inserted to justify the type (making it flush right and left).  These type galleys were pasted onto large layout sheets with rubber cement.

Most of the other contributors to the magazine were part of my college gaming group.  Though we did eventually get submissions from outside sources and used as many as we could.

Generally speaking, all issues of a print run were mailed to existing subscribers on a single day.  We would type up addresses on labels, stick the labels on then go buy postage and mail them out.  When a magazine was shipped, new subscribers usually get the most recent magazine available as quickly as we could send them out.
 

What do the codes written at the back of some Dungeoneers stand for?

I don't remember what those numbers mean.  I can take a wild guess though.  SB02 might mean subscription beginning with issue #2.  The letters could be from the subscriber's last name or a combo of initial and last name).  The final number was probably a sequential number assigned to subscribers.  Thus, James Ward may have been either SB02JWAR001 or SB02WARD001 (as he was the first subscriber).  By the end of 1977, I found that I could no longer put the amount of time into the fanzine that it deserved.  I was 5 months away from graduating and really had to focus on my studies and art studio work.  I arranged to sell the magazine to Charles (Chuck) Anshell, who ran a company called Anshell Miniatures that sold lead miniatures to gamers.  For him the addition of the magazine was a natural extension of his current business.  Chuck produced two magazines (#7 & 8) that were predominantly authored and illustrated by other folks.  I did one of the covers and sent in a page of comic art that later became the "Edge of the Galaxy" continuing parody strip.  In the later summer of 1978, Chuck went to work for Judges Guild and I was invited to interview with the company.  I probably did more work for the JG version of the magazine that I did for the one I published myself.

Judges Guild published the Adventuresome Compendium of The Dungeoneer which is how most folk know of it these days.  My six half size folios were reprinted larger and together in a single volume.  The actual original magazines are as rare as hen's teeth.  I left Judges Guild a year later in October of 1979, but continued to supply the magazine with content for another year (mostly the cartoon strip), gradually tapering off to nothing as my career changed directions towards video games instead of RPG work.
 

About how many subscribers was there?

I don't remember specifically.  At least 200 I think.  I also sold quite a few to hobby shops in the US, the UK, Canada and Germany.
 

How many magazines did you print per run (and do you recall how much it cost you to do that first magazine, and the later ones - was it cheaper doing the 1st print of the 1st magazine for example)?

I think I was printing about 500-600 copies at the end.  I turned all my receipts and subscriber records over to Chuck Anshell when I sold the magazine.  Print runs were based on how many we thought we could distribute.  Early print runs were necessarily small.  We reprinted only when there was demand.  I think we only reprinted the first two issues.  Later issues were cheaper to produce, mostly because by that time, I was working part time for the printer who did our print production and got a discount.

((Later Added)) To the best of my knowledge, only one reprint was made of TD #1 and I did it to merit demand from later subscribers and retailers.  That second reprint cover ((TD #1 3rd print)) you have looks to be a bad scan of the first edition cover.  I ran it through some Photoshop color correction and it easily slid back into its original tan color.  ((Later acknowledged there is a 3rd print))  Chuck Anshell published issues 7 and 8, but did no reprints of my issues on his own.  His editing and pre-press style was distinctly different from mine and any changes would have been obvious.

I stand corrected on reprints of issues #3 and #4.  I was able to find one of my issue # 3 �zines that is a reprint and both an original and reprint of issue #4.

When Chuck bought the magazine from me, he bought it lock, stock, and barrel (or subscribers, paste-up boards, and on-hand stock of magazines).  I retained a few personal copies.
 

Also some Dungeoneers have hand written mailing addresses to people, is there any reason why those exist?

Hand written addresses are most likely either first copies mailed to someone or fulfilling orders for individual issues.  Remember all this was done in the time before personal computers and word processing.  Typing a one-off label on my typewriter was more time-consuming than writing an address quickly on a magazine.

((Later Added)) As I noted earlier, later mail dates and/or hand addressed mail labels likely indicate fulfillment of magazine orders outside the bulk mailings we did when a new �zine was first shipped.
 

You'd ever think of writing or drawing again for some Judges Guild project (as the company still is putting out products through other gaming companies)?

Not likely to happen.  I still work in games as an artist which fulfills 95% of my creative needs.  If I want to do something else, I've got more projects than time.  And, I haven't regularly played pencil & paper RPGs in over 20 years.