West Texas is hot indeed! You might try Tyler, Texas. It gets hot, but not as bad as West Texas and no where near as humid as Houston! There is an excellent program for MSers at the hospital too. I am hoping that my youngest will choose graduate school in Texas so I can go back there.
Year round comfort zones really vary according to the MSer. Has I my way, I would probably live in Kauai, Hawaii. I spend my summers in Kansas hibernating indoors.
Because Copaxone is a prescription med and 3 years has passed, I would think an MS Specialist would want to re-evaluate you. At the very least you might need an MRI to ascertain what has been happening during your 3 year "hiatus".
MS has a variant which is fatal, but it is extremely rare. Otherwise, MS is like a series of speed bumps in your life- you have to slow down at times, but you get over them nonetheless!
If you start any med, you will have to be monitored and have your liver checked. You should also plan on seeing your neurologist at least every 6 months. With a few adjustments and learning what triggers you have (things you do, eat, or experience which can trigger symptoms), you can have a full life.
I hope y'all feel at home here!