Private or provincial campgrounds offer more in terms of facilities. However, for a more rustic experience you may want to pitch a tent on a river bank.
For fishing the river look for areas of slow moving water next to fast moving water. Fish the seams for greatest success. What you use will depend on what fish species you are targetting. Grasshopper imitations (e.g. California Blonde) will often fool rainbows in the Thompson.
On the lakes it will help to have a depth sounder/fish finder + downrigger. Get you lures down to where the fish are. Fly fishing may also produce; match the hatch. If nothing's hatching, try trolling leechs, wooly buggers, etc. Bait n' bobber (i.e. dew worms on a slip-float rig) may also produce. Ask the local tackle shop for patterns + techniques that are especially productive for the specific location you will be fishing.