Many of the interviews I found while patrolling Google were newer interviews, such as ones from 2005 or 2006, or even as recent as 2010. I did find one that, according to Wikipedia.org's article "Bill Watterson" (the only place I could find any sort of date cited for this interview, or for that matter, information about Honk Magazine itself, as cited below), was conducted in 1987 by one Andrew Christie for "Honk" Magazine. Sadly, this Honk Magazine was a bit on the obscure side, having published only 4 issues, at a schedule of one issue every 2 months over the course of 1986-87, less than two years after "Calvin and Hobbes" began its highly successful (and in the eyes of many fans like myself, tragically short) run.

The interview itself is quite lengthy, as interviews go, and I'm not certain I can quote it here in its entirety as per the posting guidelines of Mahalo, so I'm just going to post a sample of the interview, dealing with Watterson's career prior to creating Calvin and Hobbes, with a link for the full interview to follow:

"Andrew Christie: Let's start with the basics: when, where, why, and how?

Bill Watterson: Well, I don't know how far back you want to go; I've been interested in cartooning all my life. I read the comics as a kid, and I did cartoons for high school publications -- the newspaper and yearbook and soon. In college, I got interested in political cartooning and did politica lcartoons every week for four years at Kenyon College in Gambier, Ohio, and majored in political science there.

Christie: All in Ohio?

Watterson: Yes. I grew up in Chagrin Falls, Ohio.

Christie: What kind of time frame are we talking about?

Watterson: I was born in 1958; we moved to Chagrin when I was 6, sofrom the first grade on, really. My whole childhood was in Chagrin Falls. Right after I graduated from Kenyon, I was offered a job at the Cincinnati Post as their editorial cartoonist in a trial six month arrangement. The agreement was that they could fire me or I could quit with no questions asked if things didn't work out during the first few months. Sure enough, things didn't work out, and they fired me, no questions asked.

Christie: What was the problem?

Watterson: To this day, I'm not completely sure. My guess is that the editor wanted his own Jeff MacNelly (a Pulitzer winner at 24), and I didn't live up to his expectations. My Cincinnati days were pretty Kafkaesque. I had lived there all of two weeks, and the editor insisted that most of my work be about local, as opposed to national, issues. Cincinnati has a weird, three-party, city manager-government, and by the time I figured it out, I was standing in the unemployment lines. I didn't hit the ground running. Cincinnati at that time was also beginning to realize it had major cartooning talent in Jim Borgman, at the city's other paper, and I didn't benefit from the comparison..."

The full interview can be read at: http://www.kerzap.com/calvin/intrview.html

Having read this interview, I found it to be an entertaining and insightful glimpse into the mind of Bill Watterson, as he delves witfully into the subjects of his own past, his own career, his own creations, the creator of probably one of the three greatest, most influential comic strips in the history of America's newspapers (personal opinion, certainly, but one that's no doubt, given the success of the strip throughout its history, shared by many). There do not appear to be too many Bill Watterson interviews floating around from this particular era of Bill Watterson's career, so I think you might indeed find this interview useful. I hope this helps.

I found a much older interview of Bill Watterson conducted by Richard Samuel West from Comics Journal issue number 127, February 1989. His next interview was conducted 20 years after. Hope this contributes to your treasure chest.

Here are some excerpts of the interview:

-quote-

"WEST: When you look at the comics today, whose work excites you?

WATTERSON: Doonesbury, of course, has had a tremen­dous impact and influence on comics, and I greatly admire Trudeau’s work. He is probably the best writer in the field today. He can handle virtually anything - tragedy, social commentary, personal relationships, you name it - with sensitivity, intelligence, and devastating wit. He has shown that comics are not solely the domain of prepubescents. Lately, Trudeau’s artwork has become quite daring and inventive as well.
I enjoy Bloom County’s unpredictability and irreverence. In a generally brain-dead comics page, I usually find Bloom County’s to-hell-with-everybody anarchy refreshing. Opus, of course, is an inspired character.
Peanuts is long overdue for a serious reappraisal. Its ubiquitous licensing program unfortunately obscures what a well-crafted, beautifully written and drawn strip it is. Peanuts is one of the very rare strips with true heart. The sophistication and subtlety of the work is unbelievable. Comics don’t come better than this.
For Better or For Worse is very interesting to me because of its realism. I can think of no comic that has treated common, everyday domestic life with less artifice and stereotyping. I am impressed with the strip’s perception, honesty, and directness. It is also nicely drawn.
The Far Side is another great one. I laugh out loud at this strip more than any other. The drawings somehow suit it exactly. Wonderful stuff.
Cathy is visually gray, but it’s cleverly written and it has a level of honesty to it that you don’t often see on the comics pages.
After these, you have to reach pretty far into the barrel.

WEST: Before Calvin and Hobbes, you submitted four or five comic strips to the syndicates, the later ones being kind of training grounds for Calvin and Hobbes. How do you look back on that time?

WATTERSON: When I was sending the strips out, I looked no farther forward than getting interest from the syndicate, so in drawing up three weeks’ or four weeks’ material I would hope to show enough versatility and enough basic competence in writing and drawing skills that would interest them. But I lacked foresight in think­ing about the depth of the characters and whether they would actually be able not only to continue but expand as they went on. I think that’s probably the mistake that many would-be cartoonists make, that their characters are vehicles for gags, rather than distinct personalities that can grow and develop over the years.
It was a learning process. You can’t learn to stand up and walk without falling down a lot, so it’s very fortunate that I was able to do that without anybody seeing these strips except friends."

-end of quote-