practice practice practice.
When you've learnt something new, dry run it at home, practising the motions and timings.
It'll help build muscle memory to help you advance quicker.
Also, if you're going 2 hours there (kudos on the commitment) then do multiple classes in a row.
And the trick with Muay Thai is strong calves & (again) practice.
Squats at home, and practice of the basic techniques will help you un-learn everything you used to know to replace it with the Thai technique.
Your cardio will be shot for the 1st few months, but when your body catches up you'll be financially better off for the endeavour.
If brute force doesn't work, you simply haven't used enough!