Alison, dont consider starting oven cleaning without a heated dip tank otherwise you will easily double the time it will take you, try to tag along with a professional oven cleaner for a couple of days, someone who can teach you how to take the oven apart, remove and split the door, show you how to blade properly etc. You need to know the pitfalls with certain ovens, otherwise you can make some costly mistakes.
I live in a very rural area with only a very small, widespead population, I will travel up to 80 miles away for a job (usually do 3 a day in that area though), adding CC'ing means a higher ticket price for me (oven + 2 carpets is better than 1 oven). Sure, it would be nice to just make a great living from just Oven Cleaning, but every business needs scope for growth.
Having spoke to many caravan owners, damp and condensation is what puts a lot of them off getting someone in to clean their carpets. It is certainly worth considering Low Moisture cleaning methods and educate them to these methods, give them a guarantee that they will be delighted with the results (providing you produce the results!)