This is no more a DIY EV than Lego Mindstorms is autonomous robotics. It's a one size fits all kit and the fit at 15 miles and 21 mph is pretty lousy. It might be a fun toy if priced at under $500, but where's the educational value? I'd guess it uses rudimentary components (simple DC motor, rheostat, lead-acid batteries). You could get the same education building an electric RC car, plane, or boat.

The same way 3 wheeled cars in the UK (like the Morgan) were classified as motorcycles - for tax purposes.

Surging can be handled, but even a high output (180 amp or greater) engine alternator won't be able to deal with the load. That's why auto manufacturers are looking at moving to 24 or 28 volt systems in the near future. I won't get into the inverter issue but I'll make a suggestion on the 12 volt supply side for your toys.

1. Power your kit from a small bank of sealed automotive batteries (gel or AGM) which can be mounted in any orientation and safer than traditional wet batteries. If you plan on pulling power from them for extended periods without recharging (eg gaming all night) consider deep cycle batteries. Build secure mounts for them in the back of your van so they don't move around and have some protection in case of an accident..

2. Charge these batteries with a high output alternator driven from the driveshaft (do a web search on "driveshaft driven alternator"). This will only charge your batteries while the van is moving, but I do assume you're planning on driving it some of the time.

3. If you don't know how to hook up the batteries in parallel, or attach them to the alternator, or how to correctly size, crimp, and route the wiring find someone who does and do it right. Screwing up here could make things a little more intense than you'd like.

Doing it this way has a number of advantages. The two big ones are:
1. The system is completely isolated from vehicle electrics so, for example, completely draining the rear batteries won't keep you from starting the van.

2. Having the batteries and alternator both at the rear of the van makes the wiring easier.

This seems to me to be rather shortsighted and doesn't really address the question. One of the problems we see in STEM (science, technology, engineering, math) fields is that women who would be good at them tend to eschew them for the obvious nerd reasons. I have a strategy that I use with my students that has had some success. It's certainly not my idea but I have seen it work. What you should help her do is discover uses for STEM that appeal to what research has shown women want in careers - the ability to make a difference at a personal or social level. Sure, teacher qualifies, but so does electrical engineer working on alternative energy technology for developing or areas, or civil engineer working on new construction techniques for building with local materials, or biochemist working on physiological or pharmacological problems in health and disease. You don't have to design chips, or bridges, or bio weapons. And there are probably hundreds, if not thousands, of other career paths like these that she could imagine herself if you support and encourage her. Will it make her time in an undergrad or graduate program any easier? Nope. Still the "boy" culture, still plenty of hard work to do, still many times she'll want to chuck it all. But if she can keep her goal(s) in mind and remember that school is just a short time in the overall scope of her future she can do it. I have examples in my own life of whom I'm very proud so I know it can work.