Graham,
I got the impression you already have a place in Buena Park, yes? Newport is nice, but it's also one of the most expensive places to live in the country, so I'd think it's pretty expensive to stay in a hotel as well. I grew up just north of where you are staying, in Brea. I very highly recommend that you check out Carbon Canyon/Chino Hills State Park for a nice long run. It's very anti-Southern California/Disneyland feel, which will likely be a nice change if only for an hour or so. The map below shows that you just jump on th 57 freeway and head north, exit at Lambert. Head east on Lambert for several miles. I like to park just off the side of the road on the right, about a half mile past the main entrance, and just after you go over a small little rise. There is often people parked there on the weekend. There is a half-ass barb wire fence there that is broken in a few areas where people go under it. Go under it and follow the little dirt path back west for about 100 meters and then it shoots you down to cross a very small stream, that has rocks to step over it, and up to the mouth of the canyon. You can head up the north trail and loop back through telegraph canyon for a really nice and peaceful, 10 miler. Or if you don't want to do any hills just do an out and back through telegraph canyon. The place is gorgeous and will be open so long as it didn't get heavy rain the day before.
The red star here is Disneyland's location.
Ignore the red star on this one, mapquest just puts it there because I put "Brea" in for the search. It'll take you about 15-20 minutes to get from Disneyland over to Chino Hills State Park. It's worth it, I wouldn't have taken the time to post the maps or respond otherwise.
Not too sure about swimming, I swim at my gym.
(Damn, those two pictures were the hardest things I've ever posted to this forum! It kept posting previous maps I was looking at, very weird, hope you are able to check it out.)