Doesn’t seem like theres many climbers on here so here goes.
I’d recommend going to www.gymjones.com & reading through the knowledge section. Theres a lot of great information on there from Mark Twight. You can also check out the schedule on there & go back a few years to when he was training climbers.
A lot of people like to carry a lot of extra weight in their pack & do training hikes. I found this boring, so instead if I go hiking I just like to go fast and light.
Right now I’m training for a 2month trip down to the Cordillera Blanca in Peru & I started my training w/ a bunch of heavy lifting. I mostly focused on deadlift/squat/clean/snatch/thruster type lifts. For the last few months I’ve been doing circuit training like you’d see on crossfit or Ross Enamit’s site. In the past month I’ve ramped up my hiking type stuff & am feeling really strong in the mtns.
The best advice I can really give you is to just go as light as possible and hydrate & use gu. It makes a huge difference and is key if you are planning on doing big 15, 20hr days.
Rainier is a piece of cake & I’m sure you could do it ‘off the couch’ if you pay attention to proper nutrition & hydration & are mentally there.
If you have any ?s feel free to ask.