We really liked staying in Springdale when we went in October. The town is mellow, geared for tourism, and small enough that you can cruise to good coffee (the Mean Bean has really good sandwiches, too) and dinner via bike. There is a nice little shop in town there, just up the road (closer to Zion) from the Mean Bean. They actually had a stock of singlespeed cogs and a really nice mechanic.
You just drive down into Rockville and head up the dirt road from there to get to the Mesa. Kinf of a long drive on dirt, and don't forget to check all the washes on the way for jackrabbit sightings. We saw so many every morning...
Also, if you are into camping, Zion's camping facilites are really pretty nice now. You get the usual close quarters of any Nat'l Park campground, but having a nice patio with good beer on tap 100 yards away makes up for any inconvenience. Oh, and the little grocery/deli next to the patio has enough fancy cheese and imported hams to make any Angeleno happy ;-). Plus, it is worth it to take a cruise up the Zion bike path - so pretty.
I'd agree with Chucky. If you can swing it stay in Springdale, which is just outside of Zion NP. Great scenery, lodging, food and mojo. If not, Hurricane is about 20-30 minutes closer to Gooseberry than St. George.
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