Personally I would shoot for a very common, capable and fairly easy to work on vehicle. I would think one of the common pickup trucks would be ideal. The F-150 is, I have been told, the most common truck out there. The engine and suspension remained relatively unchanged for decades. If you toss out the AC and power steering the area under the hood is roomy.

A Ford Ranger or Toyota truck, both very popular, have a lot going for them.

If your main concern is vulnerability to EMP, natural or man-made, the fact that all these vehicles is common means you can go to a pull-it-yourself junkyard or used parts place and buy the ignition modules and other EMP vulnerable parts in considerable numbers cheap. Store the spares in a shielded container and switch out as needed. With practice, and possibly the creative use of connectors, the few parts shouldn't take very long to change out.

The F-150 design predated electronics and it might be possible to get one that avoids the problem entirely or retrofit a more modern F-150 with older, non-electronic, ignition system.

Any of these pickup trucks would give you far more to work with than a Beetle. They all have compact camper tops that can be fitted and all are capable of towing a trailer. Within limits and not necessarily at the same time and the full-sized F-150 gives you more capacity than the mid-sized units but all give you more than a Bug.

All three makes also have a lot of aftermarket gear available. Lift kits, winches, skid plates, heavier rear axles, performance parts are all pretty easy to find.

The things the Beetle has going for it are weigh and fuel efficiency but once you load in a bunch of gear you're going to lose a lot of those advantages.