I live in Tampa and am going on the Radiance for the same trip only leaving Dec 2. I'll try to quickly post my thoughts here before you leave later that month! Ok-the Embassy Suites you are staying at are located ALMOST a walk away from the docks-the parking question would be either way in my opinion. Which is cheaper? I don't think the parking for the cruise would be unsafe; they share the parking with a busy area called Channelside (shopping, eating movie area). The hotel you're at is very nice, no worries there.
Busch Gardens all the way, even before the aquarium. I hate to say it, but for a town situated right on water, our aquarium is a little disapointing and expensive. Instead of dining at the Columbia (very over-rated tourist thing), just walk around Ybor. Its completely safe-just stick to the main roads. You may be panhanddled a little, but the shops are very interesting and there is a little museum too. There is a trolly that runs from Channelside (where you are staying) right into downtown Ybor for a small fee, so you don't even need to drive there.