If a hotel isn't full, oftentimes it will allow an early checkin if it is arranged in advance.  Just ask the desk clerk when you call in.  All it really requires of the hotel is that it arrange for maid service to that room early.  Most hotels will accommodate.

Most Hotels Will Accommodate A Guest...

with a special need.  Ask if they can accommodate a late check out, or a very early check-in, or see if they have a day rate.  

Many people use hotels to freshen up between a flight and a meeting, before a speech or presentation in the hotel, or between staggered meetings.

Most hotels will have a day rate for that service.  I have used several nice hotels for this.

Ask for an early check, around noon or so. If they have a room available (ie..housekeeping has done their "thing") they'll let you check in.

Asking for a late check out might be a little more difficult. Even if it's available, you'll probably only get until 1:00. If you want to keep the room until 5PM you'll have to pay the day rate which (I think) is usually slightly less than half of the full night rate.

Although most of the time I do outcall only, much of the time for the sake of discresion the gent will want the room in my name. I just make reservation as usual then call that morning and let them know I will need an early check in as I will have been driving all nite and need to freshen up before my presentation. Have checked in that way as early as 10 am with no problems.

Go to any "no-Tell" and check in... when you check out, leave the key. Motel 6 will do. Plenty of those out on the pike...or off I-40