A bit of a thread resurrection.
Good to see there's a bothy thread on here, I'm a big fan of them, have used many and have attended a few maintenance days (work parties) over the years, where any help is appreciated regardless of what DIY skills one has or doesn't have!
Fair play to you on getting loaded touring bikes to some of those bothies. Some landowners' idea of a "landrover track" can be pretty steep and rough and I've walked in to some of the bothies mentioned thinking I'd struggle on a mountain bike!
As has already been mentioned, the MBA website is a good source of information on where the bothies are and how to use them responsibly. Membership is worthwhile as the yearly membership fee helps go towards maintenance of these facilities.
The UK bothies forum at
https://www.tapatalk.com/groups/ukbothies/ is worth a look too. Some parts of the forum require logging in to read (creating an account is free) but the threads for each bothy, organised in subsections by region can be accessed without logging in. Plenty of stories and photos over the years.
I'm gradually trying to spend the night in every MBA bothy so if anyone wants some (unfit) company for bothy trips let me know!