From
San Francisco to
Portland, I would do either
Klamath Falls if you want to stay inland, or
Crescent City if you want to drive along the coast.
Assuming you have the extra time since you're staying overnight and driving over 2 days, those will be more interesting stops than just staying on I-5, which is the fastest route but the least fun.
In Klamath Falls, maybe try
Maverick Motel or
Golden West Motel, both are budget hotels that have clean rooms.
In Crescent City, you could do a campground or lodge, or look at
Pacific Inn.
