I used to play quite seriously. Most of my opponents were from a local Go club I found. We had quite a number of members ranging from between 20k to about 3k-ish. We had a few regulars who were pushing 1dan, and every once in a while we would get a 3dan in for a mini-seminar. I also know that at least around here, if you want lots of good players (>5k) and were willing to put up with more than a little hostility and probably loose a bit of money, there were quite a few Korean go parlors located in the more Korean parts of the city (Chicago).
I strongly recommend you visit the AGA and look up any chapters near where you live, you might be suppressed by the skill of players you will find playing at your local go club.
As for internet go, I can hardly believe you are having problems locating opponents on KGS. Last time I was on (which was unfortunately about a year and a half ago) I saw lots of players of virtually all ranks. You can also try you luck at IGS, but I often find that IGS players, while more skilled, are also significantly more hostile to English-speaking players.
Also, if I may ask, how long have you been playing? 5K is a pretty good rank, and I find it somewhat surprising that someone could reach that rank without regular opponents of similar skill levels.
"Well, if I am not drunk, I am mad, but I trust I can behave like a gentleman in either
condition."... G. K. Chesterton
“questions are a burden to others; answers a prison for oneself”
