Pontoon boats can fit in almost any car except for a smart car. This past long weekend I took a trip up to Kamloops for some trout fishing. In my VW Passat sedan we fit an outcast 9 ft. pontoon (with standing platform), and an 8 ft. pontoon boat, 4 fly rods, tents, sleeping bags, pump, 5 days worth of food, close to 100 beers, nets, 2 pairs of waders and boots, oars, gear, etc. Oh yeah and 2 regular sized people were able to comfortably fit in it as well. We could have fit even more stuff if needed and I was still able to fully see out of my back window. All this without even using the roof racks!
If I were you I would certainly go with a pontoon boat. One pro I did not see mentioned is how far one can go on a lake with a pontoon versus a float tube. I would love to see how long it takes for someone to get from the boat launch at Roche Lake to the good fishing holes (not including monster bay) with a float tube! Couple that with a windy day (which is normal for Roche) and you have almost no chance!
One pro for the float tube is that you can travel with it on planes to other fishing destinations throughout the world as it can fit in your suitcase easily with room to spare.