I agree with Lance on the fact that pontoons DO get you blown on the water like a sailboat. Maybe the sailboat reference is a far cry from what it is, but it definitely decreases when in a float tube/pontoon float tube such as the navigators from caddis or the TU stuff. Delta tubes/ponttons are real nice also. There are a myriad of models/brands. In the end, it's your money. Sierras are small lakes anyways unless you fish Crowley or similar. If you're really out of shape...you can always add a trolling motor to a pontoon boat
THE reason why you don't get blown to the other side of the lake in a float tube is that a very good portion of your body/torso is in the water acting like a drift sock or sea anchor and you can point your fins down or in a direction that slows you down. I've fished on a lot of the Sierra lakes, as well and I can tell you that trying to hump a full pontton is hell unless you have a 4x4 and can carry that damn thing over 5miles roundtrip esp. if you go to the real good lakes.
A float tube sucks bcz you can't drink beer since it's hard to break the seal and keep breaking it. So, stick with a flask of your preferred poison. If you have the money, buy the Force fins. Yeah, they're 100.00 but you'll be glad you did when you try out a cheaper brand first and then buy the set (budget willing). At the very least, don't buy the 20.00 fins. The Float cat and supercats are nice also.
If you're gonna but a pontoon boat, buy a canoe.
As for a rod, buy a St. Croix, TFOs are ok, but buy something that has mod to mod-fast action for starters. Spend the money on a good, solid rod. 150-200.00. The reel is secondary and you don't need a reel with conical drags yet. You gotta learn to cast, hook them, and fight them. A 150.00 reel is just going to set you back in learning to cast properly if your budget is 300.00. Spend no more than 100.00 on the reel.
If fishing the Sierras, I highly recommend floating line (of course), but MAKE sure you buy some intermediate line (stillwater 1-2in sink rate clear). It gets a little stiff in cold water, but you NEED to stretch out your line everytime you fish anyways. Very important that you do this!!! After that, don't don't don't go casting for the other bank. Learn to place accurate casts you can manage and control the line at your feet or on your lap if in a float tube. The whole reason why you're in a float tube/pontoon is to get closer...remember? THE double-haul comes abit more naturally after you get the mechanics of casting down enough to time the haul. Learn as many different cast types you can and then you'll find you need to make some up as you go. youtube is a great reference on casting technique.
As far as people to read on for casting technique-nobody IMO does a better job than Gary Borger. His method is the easiest of them out there. Doug Swisher is good for advanced stuff, but so is Lefty Kreh.
Send me a PM if you want some more info. Bob Marriot's would be a good place to start. If any guy at any fly shop says you need to spend money on a good reel, they're not getting down to fundamentals. Spend the 200.00 on the rod and get a reel (does NOT need to be disc) and don't chince on the line. Scientific Anglers Ultra 3 AST or Mastery/Sharkskin, RIO Windcutter is GREAT line (what I use), etc.., Cortland 444 SL and up. DO NOT GET A DOUBLE TAPER LINE-you should get a weight forward (WF). Your priority is rod, line, then reel. Do some more research before walking into a store. And for the sierras, don't exceed a 5weight.