Redding is a city in the northern part of central California.
North towards Oregon
Getting out of Redding is a bit difficult. The I-5 passes through Redding, but getting on is not so easy. There are three entry ramps: one towards the south, one towards the north, and one in the middle of town. The one towards the south (off Cypress Ave) has a decent set up for pulling over and visibility and the cars enter very slowly, but it's a lot of local traffic. Perhaps a sign saying that you want a short ride would be useful? Towards the north end is the 299/Lake Blvd entrance. There's a little island you can stand on in the middle, for cars entering from either direction, and room for them to pull over, but the cars are moving pretty quickly and most people seemed surprised at the mere sight of a hitchhiker, so you should probably expect a very long wait. It's a bit of a walk from town, but the local bus (The Red line and the Gold line? Something like that.) passes right by. The one in the middle of town is a split-traffic interchange. There is a fourth entrance, a bit further north off Market St. If you can get there, that might be a better way to go.
North or South
While hitching in town is horrible (no good spots, cops will harass you), there is a truck stop about four miles south of town that is very easy to get a ride out of. Many people headed both North and South stop there to fill up gas and get stuff to eat. If you fly a sign just next to the door of the convenience store, people will come right up to you and offer rides. If you are more proactive and go out and ask people where they are headed (maybe offering cigarettes or gas money) you can find a ride very quickly.
Accommodation and Sleep
There's only one shelter in Redding (the Good News Rescue Mission at 2842 S. Market Street), but if you have a tent, the Lutheran Church on Hilltop Rd has a lot of space if you ask nicely and agree to be gone by 06:30.