Here's my suggestions:
Over the counter products
OPTIONAL STEP (if you have a lot of time) - Clay the van using whatever claybar kit you can find over the counter. 3M and Mothers has retail kits. They're all pretty much the same in my experience. Figure 2-3 hours to do the van. Time consuming but worth it if you really want to go the extra mile.
Step 1 - Polish
Meguiar's #9 Swirl Remover OR Mother's California Gold Pre-Wax Cleaner - They usually carry these items in PepBoys, Autozone or Discount Auto, etc. Sometimes I see one or the other in Walmart and Target. I've used these on and off over the years and they both work pretty well. And they're not stupidly expensive. They will clean and polish the paint in one step, providing a good foundation for waxing/sealing.
Step 2 - Wax/Seal
I recommend a fully synthetic polymer sealant instead of a true wax. The reason is because they are less work to apply/remove and they last longer. They don't shine as deeply as a good wax, but I think you'll find the trade-off worth it in your case.
Meguair's #21 Synthetic Sealant OR Meguiar's NXT Generation Tech Wax. I haven't personally used #21, but have used Meguair's other stuff for years and they are solid products. The NXT is on the expensive side for what it is, but delivers good, consistent results. I've used it on my wife's cars from time to time. It's a little 'clinical' or 'cold' in terms of shine, but hey it's not like you're taking the Caravan to Pebble Beach or something. You can find these pretty much anywhere; Target, Walmart, etc.
Mother's California Gold Sealer is also a pretty good choice, though I haven't used it in many years. Truthfully, the over the counter retail stuff is pretty similar to one another.
DO NOT BUY THE SPRAY STUFF It is okay for between waxes but doesn't do a good job without a proper foundation and lasts about as long as it does for you to apply.
OR
Order online
You can buy 1 container of Klasse All-in-One at autogeek.net or properautocare.com and do everything in one pass. It is not cheap, but I swear by it. It can be applied by hand as well. Take a look at the SAAB I did in my previous posts. Wonderful stuff.
There is MUCH FANCIER stuff out there, including the Blackfire line that I use for my own car, but nothing in my experience can beat Klasse for effort vs. reward.
Either way you choose, keep these in mind:
1) Do not work in direct sunlight. Find a shady spot or borrow a friend's garage if you can't. Sunlight will heat up the product and the paint and you will have a big streaky mess on your hands.
2) Use a good microfiber applicator. This is very important. When you are polishing the paint, you want a certain amount of 'cut' so the imperfections are "rounded off" and hidden. In my experience, you simply can't achieve this with a plain cotton terry cloth. I use a DA polisher and they make pads for each job. Moglet does all his work by hand, and maybe he'll chime in with what he's using.
3) Use clean towels to buff off the product. Go to Target and buy a cheap pack of Voom microfiber towels. Throw them in the gentle cycle to wash once. Dry them on low or no heat and they'll be ready to go. Make sure they're clean! Years ago I made the mistake of reusing the towels I washed with to do the detailing ---EPIC FAIL!
Hope that helps.
M