Yes, most definitively IF...
It is conveniently located. This is everything.
It is private.
It is climate controlled, not cold in winter or swealtering in summer.
We can bring our own beer, or buy suitable at the location. (We are fairly picky)
We can bring the snacks we like, or buy suitable at the location. (We are fairly picky)
What I really like is:
Having a big table with lots of room.
The ability to rent miniatures, especially if we could "call" ahead and say we need 30 orcs, 20 hill giants, and assorted trolls; and they are ready and painted.
A projector to do maps on the table would be really nice, or some battlemap prep help.
As for your business plan, I'd focus on the higher end of the market and not rely on instore sells to support this. Think of this as providing a service to people with far more money than time, not a service to those with inadequate space. You are basically setting up a club, where the well-heeled gamer can buy convenience.
I'd structure the costs two ways, a fee to join (may be monthly or annual) and a few to use the room. I'd keep it a flat fee, maybe half day and full day. Since you are providing a high end service you may even want to consider it a reservation fee, that is refunded if you show up. You are only going to have a small number of groups because you don't want to tell your customers, sorry that night is booked.
Given that you should charge mayb $50 per month, maybe $100. Seem high? Not at all. We are talking about catering to people who are making well above $100K a year. Convnenice is everything, a $50 dollar price point is nothing. Renting miniatures should be "cheap" to encourage it and it is really a huge margin in the end. Maybe $2 to rent up to 12, $5 up to 20; $10 up to 50; if more than 50 negotiate. On food and drink, this can get touchy deending on local regulations, obviously you'll want to avoid having to get some food or beverage license. Providing a fridge may be enough OR picking it up for the group and charging a 10% of item cost for the service could work. Handling the logisitcs of ording pizza, providing plastic plate and real glass to drink out would be nice. Again time is money, you save me an hour of time, you saved me about $100.
However, even selling cans of soda and bags of chips could require a license.
I know I'm not common in this desire for convenience or the ability to pay for it, but then again if you can turn a profit on just a handful of groups then you could probably find 6 other groups like ours near a big city. We are also great customers when the expereince is convenient. For example, I get offers to custom order things for me that are not in stock. I don''t do it because I don't have the time to plan on coming back, booking a trip to the game store is low on my calander. However, if I was there regularily, I'd easily buy things custom order, and wouldn't think twice about spending $100 a month.
I'd like to see something like this, hence my lengthy response.