Hello ! I hope I can help some. Rental rates,of course, can be reasonable in one area and jump vastly 10 mi. down the road. Also, depending on how desirable or "touristy" the body of water your on can make a huge difference. A good way to find out is to look in a local paper for rental advertisements and base what the going rate is for what you're looking for. In my area, a 3 bedroom mobile will run you $350-$600 with some utilities included with the higher rates. A home can be run as high as $1500 a month. Also, some will take deduct from the rent if you do some improvements and such. I hope this helps some, but if all else fails.. contact a property manager in the area, or maybe a Realtor. Now...If you're still looking for a lake rental, I might just have what you're looking for. I have a client (the home is for sale), that agreed to rent his home for $800 - $850 a mo. It is on Angel Island in Bull Lake just outside of Troy, MT. Although it isn't lakefront, we are an actual island and all homes on the island have the amenities that go along with owning lakefront property. There are boat slips available for residents, boat launch, 2 private beaches, club-house, tennis/ basketball courts, and as on. You don't have to get off the lake before 10pm like the public boat launch/ campgrounds. It is an absolutely wonderful place to live (I live there). I don't mean to make it sound like a resort, it is definitley true to Montana beauty and lifestyle. There is tons of great fishing, here and all around us. We are located across from the Cabinet MT. Wilderness Area. Here is a link to the home if you're interested.