It really depends on how you want to fish the creek (nymphing fast water, slow water fishing..) If you want to fish fast water, I would recommend the very top section of the creek, above access one (just fish the opposite side as the resort), right now blood midges and small dries seem to be producing.  If you want to fish slower water in waders, I recommend fishing access 4 and 5 (and below) with 'buggy' nymphs (pts, probably blood midges, and olive hare's ears). Everyone here has there own preferences, and any number of patterns can work on a given day. Good luck on your first trip out. 

whenever i try a new water i accept the fact that i will be doing more exploring then fishing, it pays off, and putah has alot of spots that hold fish, i personnaly stay away from the big slow moving pond type water, and the resort area near the damn stays pretty crowded so i dont fish it, personally i think the access area around #2 and #3 has the best overall looking water, two weeks ago i fished around access #5 and i think the water is just to shallow in there with flows around 55 cfm's, you get above the big shallow riffle around #4 and #5 and theres some pretty good water, anyways i beleive someone once told me that putah does not give up her secrets very easily, i've been learning to fly fish on this creek for about the past 10 months and whenever i go somewhere else like some wonderful sierra stream, it just seems so easy compared to putah. good luck and dont let the first trip descourage you, oh yeah i hope your good at ROLL CASTING !