As far as MDE is, I stayed at a really nice hostel there, they have 1 person rooms up to the typical guest numbers per hostel room. Great price, the owner is from the Bronx and it's in a quiet safe area near down town within walking access (but my definition of within walking distance is a lot more than compared to others') to the metro that can take you all over, with restaurants and a few clubs nearby. I have to do some digging to find the number, but I really recommend this place.
Nonreving down there isn't too bad. Spirit is great to nonrev with, once was I not able to get a seat, the most part never a problem. UAL is a bit stressful sometimes, numerous times have I had to wait to the last minute before I had a seat and there are no flights back to FLL in time for me to catch Spirit. If you go UAL or Delta you will have to buy a ticket as they only go to BOG. Spirit has direct to MDE out of FLL but the flights depart about 10/1030am, and the crews are awesome. I go so much the gate agents in FLL and BOG know me. Jetblue is starting or has started service to MDE, but the fee is $90 each way.
One other thing about Spirit, they charge $15 to leave and $50 to come back, but for the last 6 months or so I haven't been getting charged. Be prepared to pay it anyways.