To be perfectly honest, my ideal weight (determined by three separate tests) is 215-220 pounds, due to the density of my bones and muscles. And my thick skull, of course. I am slowly losing, and should be there by next spring.
As for Mt Rainier, the parking lot is at about 4800 ft. meaning almost 4000 ft elevation gain in 4 miles. It is not a simple climb. The entire climb was in knee deep snow.
I did Mt Si twice, Squak Mountain and Tiger Mountain and several times up Rattlesnake Ledge before we climbed Rainier. Next year I will summit!
You can look those climbs up on the internet.
Congratulations. I couldn’t do that kind of vertical elevation gain, esp. in snow. Have you tried snowshoes? They would be good in that much snow. They also feel good on aging ankles and knees. I use Redfeather, but there are other good brands, like Crescent Moon. Snowshoeing consumes more calories per mile, and is therefore great for weight reduction.