As already mentioned, Republic does seasonal service to EYW from both DCA and CLT. If I remember correctly, we start CLT-EYW in September and stop in May. There were 2-4 departures daily. When we used to have 86 seats on the 175, it was near impossible to take a full load out of EYW. As a matter of fact, I think US Airways only authorized a capacity of around 82-83 to help mitigate the weight restrictions we normally had out of EYW. Now all the 175s have 80 seats, and a full load is usually not a problem. It can get a little tight with an alternate, and some days may just not work out, but I would hope they'll do their best to get you on. I have never done EYW-DCA, so I can't really speak for the weight restrictions there. Landing in EYW with a full load is usually never a problem, as long as the runway is not wet. The EYW station manager says Airtran and Delta never seem to have problems with weight restrictions, so they may be more reliable. Cape Air runs a 402 between EYW-RSW several times a day, so perhaps they can help you out as well.