Interesting.....as I have a vested interest in both ends of your spectrum. I have been a 488 user for 18 years and although I'm phasing it out as soon as I've finished off a number of tracks that really need to see the light of day, I've learned most of what I know about recording (which, arguably is hardly anything !!

. Not really !

) on a doing level on it. It's a great machine and I'd never knock it. If my memory serves me right, you can record 4 tracks at once although acoustically it is only two as there are only the two preamps.
As for recording in the car wash, definitely !
If the reverb is as you say it is and you like it and you are able to do it, then do it. If you don't you'll be forever kicking yourself at the spurned opportunity. Even if it turns out to be one big mush of a reverby recording (which it shouldn't), it'll still be worth it. After listening back to a song or two, you'll quickly find out whether or not it's a goer.
Recently, I did some recording with a drumming friend in the warehouse of my company. Even though it was zero degrees the first time and progressively colder the second (my fingers hurt each time I plucked those bass strings), it was worth it and we got down altogether about 10 useable songs. And the rats never turned up, which was a plus ! The acoustics there were, um, different, and I tried a few experimental things like putting a "room" mic in the back of one of the vans. I think your mic idea sounds pretty useable; maybe on the first session, you could spend some time just experimenting with various placings. If you look back over the "Recording techniques" section of Home recording, you'll find some fantastic bits on miking, like this one;
https://homerecording.com/bbs/showthread.php?t=290919
It's worth reading back through a variety of threads because they quite often go on these sidetracks, slightly off topic {I call them 'sidechain inserts'} in which these pearls of wisdom and nuggets of gold come up. They may have had little to do with the original topic, but they tend to be highly useful and useable bits.
Enjoy it and your songs.
