Fat guy beginner skiing tips

I'm 5'10" 350 lbs and have a ski trip with colleagues coming up, I will not be the guy that just hangs out at the lodge bar.

I went skiing once when I was 12 and by the end of that trip I was able to make it down a green trail, but never tried again. I'm 33 now. Went once last year and never made it off the bunny hill due to the excruciating mid-foot cramping caused by the horribly fitted boots I rented. Did progress to the point of parallel turns though, quick learner. Believe it or not I used to be quite the athlete.

Just picked up a seasonal rental from an local Indy shop and am fighting the cramping again, but going to keep wearing these things until I'm used to them.

Looking for any guidance in any form, I'm planning to get a few days of practice at the local Hill (Mohawk Mountain, CT). Am I still wearing the wrong boots? What should I be focusing on to learn as quickly as possible? How do I not embarrass myself?