Boatyards are another good option for this, power, workspace, accesibility and other issues are solved, and if you're not driving the van during the covnersio you don't have to worry about moving it.
Watch home depot for sales on tools,
Milwaukee 12v drill, impact driver(couldn't live without it) LED flashlight, and a cordless sawzall called a hackzall plus batteries and a charger were on special a while back, 149$ for the set.
This week should have good sales as well.
I prefer milwaukee over Makita for their tool selection(far better, car chargers, heated jackets, vacuums etc)and their aggressive sales, we use these tools all day every day at work, and out of the 3 kits I've bought(plus at least a dozen single tools) I've only ever had one problem, and that was an out of the box alignment issue on the jigsaw.
A good cordless jigsaw, and blades will go a long way to filling the gap left by not having a circular saw. Festool blades are expensive but they are the best for anything specialized, for the regular old plywood type cutting I use the bosch clean cut or progressive blades.
I can cut up to a 4x4 wood post without issue(extra long extra ridgid blade), metal(short and long blades), fiberglass(carbide tipped blades) even foam insulation(serrated knife blade) with the festool blades I have.
Using the same batteries to power my shop vac, which gets connected to the jigsaw means that no power is required to do basic cutting cleanly. A little slower than a circular saw, but it will get the job done.