Hello Shawn welcome to the forum!
For reliability best bet is a 4 stroke kit. If you are familiar with and good with wrenches you can make a reliable 2 stroke as well. Depends on your selection of wheels, drive and braking system - your skills as a mechanic. I run 2 stroke engines. Built roughly 25 or so over the past 9 years. 3 sons and a couple friends run bikes I've built.
As you continue to think about what you will build, remember @ 200 lbs and the hilly geography common in Maine, your goal should not be focused on top speed but torque. Low end power will be most appreciated. I weigh about 155, run a 48 t rear sprocket on a 29" bike Also a 26" bike with the 41 t rear sprocket. Both can top out at about 35 with a tail wind. At my age (59) I realize a catastrophic event on a bike WILL hurt me so I am very happy tooling around in town and rural areas 18 maybe 25 mph on a good day.
Whatever you decide 2 stroke or 4 - there is a multitude of talent right here on this forum who can guide direct and help you through any prob. you may have. Best of luck to you! and if you are in the Bangor area I would be glad to meet up sometime.
You can see most of my work at the link below. Select "Albums" Tab
https://motorbicycling.com/members/allen-standley.33548/
