For people covered by Medicare, how well are treatments for TOS/brachial plexopathy covered?

I have a good chance of being on Medicare this year assuming my SSDI appeal is successful. My workers comp attorney wants to settle the medical portion of my workers comp claim, under the assumption that Medicare would cover most of my medical costs, and that Medicare would be easier to deal with than the workers comp carrier over the long-term.

I'm concerned about how much of my current nonmedication treatments (massage therapy on neck and arms for brachial plexopathy at outpatient physical therapy center, hard and soft splints for inoperable carpal tunnel that need periodic replacement) , would be covered, as well as future treatment options (surgery if needed, etc.). I'm also taking Lyrica for nerve pain.

I did hear from my pain management doctor's office that the outpatient lidocaine infusions I get twice year for type 2 CRPS (RSD related to the brachial plexus injury) is not covered by Medicare, because they consider it "experimental."

Also, looking at the Medicare web site, I found that there is a $1780 per year limit on outpatient physical therapy for Pennsylvania.

Has Medigap insurance (the type that includes coverage for "Part B Excess Charges") been helpful in covering payment for treatments not specifically covered by Medicare B or where physical therapy, etc. is needed beyond the medicare cap amount?

Thanks

ThreeforOne