Think about putting sponsorship on the back burner for a while, David. Running as an independent has the advantage of being able to pick and choose what you what to run and where you want to run it. You get good enough and they'll come looking for you - and with a much more lucrative offer...
Understand the desire, David. Honestly, though, RC tracks are for those weel-heeled with deep pockets. Maybe better for now to use your discretionary cash chasing regional and maybe a national event? Get a bucket load of racing experience under your belt before taking on managing a track...