You can pre-scent by leaving the thaws rat right near the cage. You don't need to go through all that separation thing.

For one snake, you can just heat up your feeders in warm water until the rat is warm all the way through.

If you have a hair dryer, you can heat up the rat a little more before offering it. If you use the hair dryer on it as the same room as the snake, it will do a great job of pre-scenting the room for you. Mmm Hot nasty dead rodents..

I thaw all my rodents on empty strips of flexwatt set to 92* with a reptile thermostat. It takes about 4 hours to thaw them this way. The warm water would probably be a little faster for one rat.