Shane - if you prefer to stay on-site at WDW (which we always do and heartily recommend), then you have the free buses to the Disney parks and also you can pick up the Lynx shuttle buses direct to both Seaworld (service 50) and also Kissimmee Old Town (if you like) for just over $1 per trip - you catch the Lynx buses from the TTC near Magic Kingdom.
www.golynx.com\routes.cfm
Universal from WDW is a little more difficult - I think 3 buses if you go by Lynx. You can catch the Lynx Seaworld service to the bottom end of International Drive and pick up the I-Ride trolley and go up and down International Drive for cheap places to eat.
www.iridetrolley.com
For accommodation, I would recommend Pop Century in WDW, however, this year mid to end of August (when we are going, there are some great deals - the free dining offer with package deals direct with Disney - the Swan and Dolphin at $129 or you may wish to rent points from a
DVC member on these boards. If you want to visit Universal, the on-site hotels there are expensive for 1 person - you may wish to stay a couple of nights or so in a hotel on International Drive (maybe near Seaworld) so you're closer to Universal.
You can also buy a book with lots of good deals (the vast majority are useful if you're staying offsite) - it's called the Entertainment Book and usually costs $30 and runs to the beginning of November each year - if you buy it in early summer though it is available at a greatly reduced price - they're offering it at $12 at the moment plus $5 postage to the UK. They used to offer a coupon which gave big discounts on Universal on-site hotels, but they don't anymore - this is why I bought the book last time. There is a good meal and movies deal coupon, according to the US boards a meal on and movie at Universal's Citywalk is free - I need to check this one out!
www.entertainment.com/discount/home.shtml
The first time I went to Orlando, I went alone - we have been several times since with family, but I had a great time as a free spirit doing my own thing - enjoy.