Smithville is a good lake. Truman IMO is the best lake in MO, Ton of big crappie, withought big boats of LOZ.
What area do you live in? For me, in Lees Summit it makes more sense to me to go to Truman rather then Smithville, but I also fish the Jackson Co lakes a lot.
I belive Smithville is 18.00 per day, or they sell a yearly pass. Truman is 3.00 per day at the corps ramps. Plenty of free ramps also.
Do you have map chips of any kind for fishfinder or handheld GPS? This is a must have to me, Lots of Timber on both lakes. Although you can navigate a lot of Smithville without it and still catch fish, but on Truman I wouldn't go out without digital maps.
W is the highway that crosses Smithville, and there is a ramp there. A lot of people fish the bridge pillars. Fun place for the family to catch a ton of fish.
Hope some of this helps.