Ok, here's my Keys advice. I've only been once, so take that for what it's worth. I did a lot of research on TripAdvisor and talking to friends beforehand as well.
We flew into Miami, rented a car, and drove everywhere. We flew in early on a Saturday and out on a Wednesday. Two nights in Key West and two nights in Key Largo. Obviously you could see more if you're there longer, but what we did was very doable and allowed us to squeeze in a lot. The drive down is really pretty, and there's good places to stop along the way to break up the trip.
Islamorada:
About halfway between Miami and Key West, Islamorada was a good stopping point to break up our drive on Day 1. We ate at the
Island Grill, outside with our feet in the sand. Then stopped at
Robbie's to feed the Tarpon and see the pelicans. They also have kayaking and some other outtings available, but we just did a quick pit stop.
Key West:
I recommend staying at one of the hundreds of B&Bs in KW. Most of the hotels and resorts are not walking distance to the main downtown area, and KW is a place you really want to be able to walk/bike around. We stayed at
La Pensione Inn, and I'm sure there are nicer places, but I'd recommend it. It's only a few blocks off Duval, easy walk down to Mallory Square, had bikes available for rent, and a good breakfast. I definitely recommend renting bikes at least one day to get around to some of the places that would be a longer walk.
Flamingo Crossing on Duval had really good ice cream.
Kermit's Key West Key Lime Shoppe had very good pie, along with a number of other key lime flavored offerings (cookies, dips, BBQ sauces, candy, etc) and they had samples out to try of almost everything.
Key West Pretzel Company was good and had a ton of different homemade dipping sauces to try.
Paseo Restaurant is a hole in the wall (old converted gas station), but lunch there was delicious.
Schooner Wharf Bar was also a pleasant surprise and had live music and a great outdoor dining area/bar. We wanted to go to
BO Fish Wagon, based on recommendations, but it was closed early the night we tried.
Blue Heaven is super popular and always recommended for breakfast/brunch. I concur, but would recommend going early to avoid the long waits. Eating outdoors with chickens wandering around is definitely unique.
In terms of sightseeing, you have to go to the
Southernmost Point, just for the photo op pretty much.
The Hemingway House was definitely worth the visit and the tour (much more interesting to hear from a guide than just wandering around...but at least go see the 6-toed cats!). Sunset at
Mallory Square is a must. One afternoon we biked down to
Fort Zachary Taylor State Park to the beach there. It's a bit rocky, but you can swim and snorkel there or wander around the fort and the bike path. I don't recommend trying to walk there. Either bike or drive. The
Butterfly Conservatory seems like a random stop, but we actually thought it was really cool. Pick up a coupon book from any inn or shop and you'll find coupons and discounts for a lot of the tourist stops and shops.
It was a little cool and windy when we were in KW (in February), so we didn't end up doing any swimming, snorkeling, sailing, fishing, etc, but there are a lot of options for that as well. I read good things about
Danger Charters, but can't review based on experience.
Bahia Honda State Park
This is another beach option in the keys, and is part way between Key West and Key Largo. We left KW in the morning, picked up sandwiches in town, and planned for a picnic on the beach in Bahia Honda. It was a nice stop on the drive, and there are 3-4 beaches (albeit narrow ones) to visit.
Key Largo
There are a few hotel options in Key Largo, and nothing is really walking distance to much, so you just need to pick a place to stay that you like since you'll have to drive to meals and activities. I definitely recommend
Dove Creek Lodge. The rooms have nice views out to the ocean, the grounds are nice with a pool and hot tub, hammocks, swings, etc. They have free kayaks you can take out. And there's a restaurant/bar called
Snappers right next door that is pretty good. They also have a good free breakfast.
Fish House restaurant was great. It's not on the water, which was a drawback, but the food was delicious. The Black and Bleu and Matucambe style fish there were both so so good. Even though breakfast was included at the hotel, I'd also highly recommend
Doc's Diner. I had what I consider to literally be the best pancakes I've ever eaten. And the hash brown casserole was also really good.
There are a ton of options for snorkeling and scuba in Key Largo, and we used
Keys Diver. We were very happy with our trip, but I think most of them are probably fairly similar.
Hope that is helpful if you end up going! They Keys definitely have more options for sightseeing and active stuff (snorkel, scuba, sailing, kayaking, fishing, etc), and aren't really a beachy resort type vacation, but I think totally worth a trip.