If you want to stick to the local demographic, you need to build a strong customer base fast. Get your name out there. Get involved with the community somehow, even if its volunteer work. Get to know as many people on more than an acquaintance level as possible. Door to door is tricky, but there are better ways. Network marketing has more potential. Start with the people you know that are closest (friends, family, etc) and tell them about what you are selling. Have them get in contact with as many people as they can who would be interested (of-age smokers only), have them say that you want to give a demonstration. Once you have those names and numbers of people who are already expecting you, you call them and make appointments to show up.
After each demonstration, have them get a hold of as many people as they can who would be interested, and again, make the appointments. Each person will give you at least a few names and numbers that they will call, and you check back with the original person to see who was interested and who wasn't. From a handful of people, your customer base can grow dramatically, if you have the right approach. No-pressure selling is much more rewarding than cold-calls and door-to-door. These are people who are already interested, and you aren't showing up unannounced.
As for your supplies, yes, have some kits but don't pay too much for them. There's sources that can get you kits for $20 a pop, but you have to do some digging. Have some demo kits as well, units that people can vape on while you're doing the demonstration. Have plenty of liquid samplers as well. It's easier to have individual atties labeled with the flavors, so you jsut swap atties instead of having to clean out the atty each time. Have accessories as well. Passthroughs, car chargers, PCC's, etc. You can mark up however much you want, but just keep in mind you want to beat the mall prices and as many online prices as you can. At first.
You'll want to be legit about it as well. Get a business license, register your business name, and make sure to pay the sales taxes. Do your research on your local government's requirements for small businesses and get your business license. This will go a long way in keeping you in business. People want someone who put the time and effort into their company rather than someone who's just slangin' e-cigs.