Lived there for 13 years because of a job and school. Lot of pressure and difficult getting access to some places. Scofield reservoir has monsters, use a rusty or green woolly bugger sinking tip. Lots of crawfish in that lake. Provo is good but crowded and that will be your main challenge. Did good there with grey scuds, sow bug, rainbow warrior and Ray Charles. Fished it in the canyon not up by Heber. Logan river is good but may be high that time of year. Bear river can be good. Green river is Valhalla from what I've heard, never been. Ice off on Strawberry Reservoir is batty phenomenal but I think that's where they termed the phrase combat fishing. Went up in tubes there one year. Chunked egg sucking leach on the ice then dragged it till it plopped in the water. It was crazy action, just one of those days you never forget. I'm originally from Idaho and go back every year. A lot of Utah anglers go to Idaho now. Utah anglers have a reputation whether deserved or not as well... being less than gentlemanly fisherman. I witnessed four kicking around a fish kill up around McKay Idaho last fall as if playing a game of soccer. OK, not a capital crime but still distasteful. Yes, I did ask them if they were from Utah and one replied "yea, how'd you know?" Buy kids books.....
If you just go over the Utah Idaho line, I fished the Portneuf river and the Little Bear river in a place called Black Canyon, if I recall. BHPT, Hairs Ear and the red copper john with the white rubber legs in size #18 was dynamite. Be careful in that canyon though the wading is treacherous. Not the current but you can be wading in water two feet deep and step in a hole 8 ft deep and round as a barrel. I'm not a geologist but the floor of the river in that area is solid rock and those holes must be generated by water using a small rock to carve it out. I wouldn't even attempt it if I couldn't see bottom. BTW, my nephew caught a 14 pound rainbow on a chironomid but I'm sworn to secrecy as to the location
. Eat at Cafe Rio, best Mexican salad you'll ever lay your gums on. Good luck.