OK, let's have a look.
We don't rent a car because we stay on I-Drive. For us, it's not worth it. Where you are staying, you can get by just fine without a car. Here's wha you need to know.
1. The I Ride trolley is great. It will take you up and down I-Drive, to Sea World and to both of the Prime Outlet malls (stop 1 at the top of I-Drive and stop 42 at the other end). You will only need the red route. Ignore the green. You can buy passes in lots of hotels but not yours, you'll need to nip into either the International Palms hotel or CoCo Hotel which you'll see when you walk from your hotel onto I-Drive. A 7-day pass is $10 and a 14-day pass is $17.
2. The I Ride trolley doesn't go to Universal Studios. You will need to get off the trolley at stop 8, cross over the road and walk past the Walgreens. Then you'll need to turn left onto Universal Boulevard. Walk in a straight line and you'll soon be in the Universal Parking garage. It takes 10 minutes or less and is pretty much flat.
3. The alternative is to get a cab frm stop 8. This is easy because it's Wet 'n' Wild. A cab to Universal from here will cost you around $5. In the reverse direction, Universal has a taxi rank. It's easy and cheap. In fact, a cab back to your hotel would be less than $10 if you're too tired to walk after a long day.
4. The Lynx buses are also fabulous and will get you to and from the airport. They are $2 for a single ride, but if you need to connect to another bus just ask for a free transfer when you get on. Cash only on the buses and no change is given. They take dollar bills. It's $4.50 for a day pass - just ask when you get on the bus. A 7-day pass is $16 and they will mail these to you in the UK before you go at no charge.
5. Its easy to tell where a Lynx bus is going - look on the front! Lynx bus routes you may wish to use (walk to I-Drive from your hotel - its 2 mins away) include:
42 - will take you to and from the airport. It'll take around an hour which is about 20 minutes longer than a cab, but is $2!! It also goes to the Florida Mall (stand in the North facing side of I-Drive) and the south of I-Drive including the Premium Outlets (stand on the south facing side). This will also take you to the same stop as the I-Ride trolley, outside Wet 'n' Wild where you can then walk to Universal easily.
8 - will take you the length of I-Drive, all the way up to the Premium Outlets in the far North end (same as I-Ride trolley stop 1) and down to Sea World (face South). This will also take you to the same stop as the I-Ride trolley, outside Wet 'n' Wild where you can then walk to Universal easily.
40 - from Universal to Mall at Millenia. We tend to take the bus there after a morning at Universal, and then catch the 24 back to the Prime Outlets at the top of I-Drive (then either shopping or hop on the 8 to take you down I-Drive). A cab is only about $15 each way if you don't fancy this.
37 - you can use this from the junction between i-drive and Sand Lake Road to go directly to Universal, but it's actually more of a hassle than just walking from where the 42 drops you at Wet 'n' Wild. It also drops you back further up I-Drive. We never use it.
50 - from Sea World (take the 8 there) to Disney.
My personal thoughts are that the bus systems are so good that I see no reason to rent a car. For 2 weeks, it will cost us each $32 for all our transport needs. That's the same as three days of parking costs alone. Yep, you do sometimes have to wait a few minutes for a bus. That is the nature of the bus. But, as we are on holiday, this doesn't bother us. It also means we can chill out, not worry about getting lost, not worry about picking up or dropping off a car, paying for parking, buying gas etc. This will be my fifth trip without a car (done 7 with a car) and we are looking forward to it. Oh and if we can't be bothered to wait for a bus or it's late - we get a cab. We reckon it saves us around £300 per trip for minimal hassle.
I - occasionally - ride the bus in the UK. You cannot compare the services - the services in Orlando are a million times better than anything I've ever used in the UK.