Does bed have access to compartment going to the outside?

We just purchased a used Sundance. My husband was trying to loosen all the locks by using a lock spray and then in inserting the key to loosen the locks. Needless to say, the bottom door lock now has a broken key in it that he was unable to remove, and it is in the locked position. Wondering if the bed has access to one of the outside compartments. I don't want to crawl in there until I know.

I don't think there is access from under the bed, but you would have to look for yourself.
It looks like you might just have to drill the cylinder out and replace it. It is most likely keyed with the typical 751 key and easily replaceable.
There is the Michigan Chapter Rally being held in Traverse City in September. Just a three hour drive for you. Consider attending as well as joining the Heartland Owners Club.
Link to rally info. [LINK]

Peace
Dave

My 2011, 245 RL has a small trap door (laundry door) in front of the bed. It's only big enough for a small child to fit through, but Heartland has also welded angle iron in the opening preventing anyone from breaking in through the front door and getting up into the trailer. if you have one of these, you might be able to reach the lock lever with a stick or something similar to turn it.

Otherwise, you are looking at drilling out the lock as Dave said.

One thing you might try is to attempt to open one of the windows. You might get lucky, and one of them isn't latched, or not latched fully. Then maybe you can slide your screen over, & get in that way.