Long-term Texas hack project

[sprale]

This year, the tax return is going to my wife's home studio. Next year, I've been give the okay for another bike, as long as I can get a sidecar for it. Time to start planning for a long-term project.

I'm looking for an older (80-90s) bike to hack, preferably Japanese. I'll probably try to pick something up for $1-3k locally on Craigslist. I'll keep my newer Ninjette for commuting for now, so the hack will be for riding with my girls (daughter and wife) on weekends or when I need extra space on the commute.

I'll start looking for an electric welder this year, learning a bit before I get another bike. I've got an old Subaru and a few things I'd like to try on it for practice.

I think I want a standard or dual sport, minimal or no bodywork. I'd like to find a bike that would be easy to access and maintain with a sub-frame mount. I'd like to find a bike that I can swap out flat profile car-type tires. I'll probably match the car's tire/wheel to the bike's rear, keeping a third as a spare. I might try to build a leading-link front end, but probably not as an early step.

I'm thinking that the extra load will put enough load on the bike that I'll want to change the gearing a bit. I'll probably never top 60mph, slow is good for me. I'll also be riding this hack much more lightly than my Ninja, given the precious cargo. Any opinions on air-cooled vs. water-cooled? If I go with an air-cooled, I may at least put an oil cooler on, adding oil volume as well.

For the body, I'm not set on any style. I like the Ural-type cars, but minimal is best. I doubt I'll find one easily on eBay/Craigslist, but I'll keep an eye out for one used. There are a few companies that make new ones at a low enough cost for me, one here in Texas.

I like classic Honda's the most, like the CB750. I dig the Triumph Scrambler and Bonnie. The Wee-Strom is cool, but too much plastic. A KLR or DR650 is nice, and as a hack would be the only way I could mount one. I thought about building a hack out of my old KZ650, but it was too much a basket-case. A light-weight rig would be the best in my opinion. Ugly bikes are fine, functionality is more important. It may even end up a bit rat-ish...

Any suggestions on a starting point? This will be a bit of an ugly home-built hack. No Dauntless-quality work here.