3 full days? With the construction at DCA, you should be okay. Longer hours in June will make that easier.
Just remember that some attractions are not fastpass as they are in WDW (ie Toy Story Midway Mania). If you get there first thing, you'll be fine. Longest wait I've seen for that ride is 45 minutes - nothing like WDW.
Yes, Paul usually does recommend HotWire. I don't know if it works the same as Priceline - once you commit, you're in for good. I've never been comfortable with a "no-cancellation" policy. Anyway, most any of the hotels on those couple blocks of Harbor Blvd would be within walking distance. Also hotels on Katella. You've got a car, but parking can be $$.
Yes, lunch at Blue Bayou is a good thing!
As with any Disney park, enjoy and explore the details. Small World, Space Mountain, California Screamin', and of course Pirates - all not to be missed.
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Kathy