I-95 does not go to Orlando.If you take I-95 you can either go all the way north to the Beachline (528) to cross over to Orlando or switch over and get on the Turnpike at Ft.Pierce (exit 129 on 95 and exit 152 on the turnpike),that's actually pretty easy as both highways are right next to each other there.It will also save you some money in tolls as the turnpike is tolled and 95 is not but 95 has much worse traffic,avoid it entirely if you plan to be on it during rush hour from West Palm Beach south. The only place you will see a highway 91 is the online maps. It is called the Florida Turnpike. They have a web site that has a toll calculator (around $20 to Orlando taking it the whole way). Both are multi-lane, divided highways.
Both have exits with food and gas. The Turnpike is very desolate north of Ft Pierce, but it does have "service plazas". On a 100 mile section of road, there are only 2 exits between Ft Pierce and St Cloud.I hate driving that stretch of road especially at night cause it's so boring but the plazas on the turnpike do offer places to eat,gas,bathrooms and shops that are reliable and heavily traveled,although more limited late at night.95 has more exits but some are better than others as you might get off at 11pm at one and only find one gas station opened where you can put gas but they might not even let you inside the store to use the bathroom.So you have to get off at the busiest exits to get the most services.A lot of times I leave Disney and head south at 10pm at night so I've had the issues of getting off at certain exits after midnight and only finding limited services.If you're traveling at 2pm you should be fine.
I-95 can be very congested especially in South Florida. The Turnpike has a posted speed limit between 65-70 mph in non construction areas.I would suggest taking the turnpike as it's a straight shot,has less traffic and will get you there faster.
