Life after the endurance template

I recently wrapped up the endurance template (which I enjoyed quite a bit) so I could build some kind of strength base for my cycling goals this year. The main thing I am training for is a 100 mile mountain bike race/event at a kind of high altitude, nearly all of which is single track. I’ll be out there for at 10 hours, potentially more (I suck at mountain biking and am nearly a clydesdale at the moment). The race/event takes place in 3 months, but I’d like for my next big of programming to be sustainable since I’ll probably be riding a lot until October regardless.

I was wondering what a strength training programming might look like that I could incorporate into the large volume of mountain biking. My goal here would be just to remain durable and not revert to my previous state as a 130 lb cyclist who was just a ribcage with brittle bones. Ideally I would like to not backslide on my lifts, and if I could even increase my lifts that’d be nice.

I should note that I am probably in the expert category for cycling experience. I’m fat and out of shape now but I used to race, rode my bike across the country one summer (8-14 hour days, every day, for 3 months), and used to do ultra-cycling events where you ride for 40 hours without stopping. My cycling plan for the moment is likely:
Monday: The cyclist’s day of rest. I’d probably do a very easy 30 min/1hour ride just to spin out the legs, RPE 0
Tuesday: 1-2 hour ride depending on how I feel, RPE 7
Wednesday: strength training?
Thursday: 1-2 hour ride, RPE 6
Friday: 1-2 hour ride, RPE 7 to prep for weekend ass kickings or strength training?
Saturday: 2-3 hour ride for now, will ramp to 5/6/7 hours eventually
Sunday: Same as Saturday

This is obviously not what I would do if I was racing for real, this is just to accrue time on the bike so my hands, butt, and feet don’t feel like they are going to fall off after being violently shaken for hours on end.

As for strength training, what rep range should I be targeting? The second “block” of the endurance template focused on the 3 rep range which I think makes sense, since I’ll be getting plenty of pedaling in I can probably skip 7+. That being said I have no idea what I’m doing and maybe my instinct is completely reversed.
How many days a week should I be scheduling weight training? 1 doesn’t sound like enough and 2 sounds like too many. Would one day a week of the big 3 be enough to at least maintain my strength, or would I benefit from something like a two a day with some accessories (RDLs/OHP/step ups or some quad focused exercise) followed by a lighter cycling session?