Well I was thinking of anyone who is leaving the city and wants to stop for a good meal and cheap place to sleep. As well as any people coming into the city needing to take a break from driving.
If you're only 60km out of Warsaw then what is the likelyhood of someone stopping? Surely if you are that close to Warsaw, you would carry on driving into the city! Similarly, if you had not long left the city would you really want to stop after such a short drive?
However, I can also see the benefits. Some people may not want to eat/sleep in Warsaw and this may be more suitable for them. Having somewhere out of the city with less hustle and bustle might be more appealing.
I've seen I few hotels, motels, restaurants like this on the outskirts and around some other cities so I guess the concept works. I would advise making contact with some other places around the country in similar locations to see if they would be prepared to share some information with you.