Happily Houseless said it best...

You just can't move out and cram all your stuff into your vehicle. It takes a long time to minimize and get rid and sell all your stuff.

Personally, I find that to make it work, I'll have one set of goto clothing that is extremely comfortable to sleep in, yet presentable to hop out and walk around.

In your case, yoga pants would work fine.

It's time to let your DVD collection go. Buy a hard drive or two for backup, and rip your DVD's into ISO or Video_TS and sell off the discs. Most players can handle ISOs or Video_ts, but if you're really stuck, you can always burn the discs back on to DVDs if you really want.

On a 1TB drive, it can hold 100 DVD's easily at fully quality, but even more if you get rid of language tracks and other 'extras'.

If you're going to be a vandweller, you're going to have to divorce yourself from a consumerist clothing mentality. Invest in a few versitale, durable presentable pieces, and stop buying disposable clothes that you typically find at the mall. If you're going to invest in anything, I would suggest good cottony socks and terry cloth underwear. Those can really change those days where you feel really grubby.

Where I live is a costco, and with all the stuff they sell, there is a TON of cardstock. It's free. See if you can get cardstock. And cut it to fit your windows, then spray paint flat back.

Consider just watching movies on your phone. There must be a way to convert DVD's into phone files. But if not. I really recommend getting a tablet and a tablet holder like this http://www.ebay.ca/sch/i.html?_sacat=0&_from=R40&_nkw=tablet+arm+holder&_sop=15

They're extremely power efficient. It will run off of your car battery just fine.

And really congratulations.

in 5 months you saved 1 year emergency fund.

Treat yourself to the concert with the money you get from selling all the clothes you don't need anymore.