For ExpressJet, you'll hold EWR or ORD right off the bat, then maybe CLE and then IAH. All the bases are not out of reach.

If I had to pick one for you, I'd go with ORD since it has the most options. CLE is strange with their Florida flights (Goes back and forth from an RJ to a 737, then seasonal), IAH and EWR have a LOT of old timers with high seniority commute out of there. One FA I flew with commuted out of FLL and said it was a nightmare, MCO is a high tourist destination (as you know), so people will magically appear on the standby list at the last minute. PBI doesn't have that many options.

ORD to MIA would probably be your best bet, but it would more than likely be very difficult.

Get familiar with:
passrider dot com
Trains/Buses back and forth between ORD and MDW
SWA flights out of MDW
FedEx/UPS jumpseat websites
Program all jumpseat phone numbers in your phone
Add all airline apps (to update flight status)
Learn about the commuter clause in the contract
Carry the FIL of the latest jumpseat hierarchy

Also, carry a bible and some holy water - You'll be doing a lot of praying! Best of luck!