There’s all the obvious- availability, menu choices, layout, parking, cost, what’s included/not included, etc.
Also- are you just having the reception there or the ceremony as well? Because there are lots of other questions if you are doing both.
Other things you should know:
What is the schedule of the reception? (You don’t want it to be rushed, but some places only want to provide food service 2 hours- which means your guests will have to cram food down their throats to finish all the courses and cake in 2 hours)
How long will the room be available to you? (ie can you get in there beforehand to set up and afterwards to clean up)
Do they charge a cake-cutting fee?
How does the beverage service work? (ie open bar, byob, beer and wine vs. full bar, table service)
Do they do buffet, family style, plated service, etc?
How will they accomodate food allergies and special diets? (ie vegetarian, gluten-intolerant, nut allergies, etc)
Do they have a PA system for toasts or do you have to provide your own?
If you are doing any special elements (slide show, photo booth, etc) can they accomodate it?
Is there a room for you and your groom to freshen up with before the reception and your grand entrance?
Hope this helps!
Also check out these relevant posts chock full of info:
How to book a venue: step by step
Selecting A Caterer
PS- you can search for more relevant posts and info using the Google search tool bar on the upper right hand corner of the page!