Finally someone builds a UTV I've wondered if that is easy to do. Looks not so easy though... nice job. Too funny that you have GAS on the front when you said it is an electric. What does the GAS Stand for?
GAS is a company which I am building and selling Turn signal, light controllers and power relay boards. This is also a test bed for some of them.
I actually chose an electric vehicle because of how it is used. It may sit a while then be used for short trip moving bulky items. No need to worry about bad gas, fouled plugs, etc.
As far as building 90% is frame of mind. Obviously one would have to have some basic fabrication skills, but it's kind of like buying your first house. You never knew how to hang a door till you created a partition and hung your first door. Here was the thought process:
1. Drive train, pick type, power, etc. This includes axle, axle ratio, transmission if need be. I chose the electric motor with Cushman rear axle.
2. Chose suspension. For the rear I like the triangulated 4-link set up. It is smooth running 28mph over open field! Fronts are double wishbone using Honda 300EX uprights. Chose what you are going to do for brakes. Fronts are stock which fit the Honda Wheels and uprights. Rear are adapted to what I had. A bit of an experiment but working well.
3. Take all your knowns and set your frame around them. Knowns for me was battery compartment, motor and trans location, sitting position, bed size, feet, suspension setup, mounts, steering rack, height, travel, extra room for what ever accessories you will need, controllers, etc. You may not know how you are going to lay them out but leave enough room to work it.
4. From that sort out a general frame layout. For me it got me to these stages:
Once you got to that point you can forget the base build and work on the details
It required the roof roll bars for integrity:
Notice I only had one bar front and back across top. I eventually had to add a second to make mounting provisions for windows:
At this point it's just working out the details. Fender mounts, etc. Fenders are trailer fenders form Tractor Supply. Notice the second bar top of front and rear window area. I had to get past the curve to get a flat section to make a window opening. These are just the details you work through. There are also now tubes welded on the door frame for adding a door latter. I don't have to do those things now.
Welding on body panels to give it some sort of a body. Notice the windows have a sheet metal opening welded in. I had automotive safety glass cut. It is installed using a rubber locking seal from McMaster. It's not hard to do.
You have to plan ahead as much as you can for things, in my case, motor controllers, emergency brake, shifter linkage, gas and brake pedals, etc. This is the area under the seats. Seats were from Surpluscenter. Seat mounts can be adjusted fwd and back. Area under include mounting for motor controller, large high power relays, shifter and emergency brake, etc:
Brake is Wilwood, accelerator I bought at a swap meet. It is for an over road truck I got at a swap meet for $10. I 3D printed an adapter to use the potentiometer I needed for the controller.
So any way this was my thought process. In short, Big picture of what you want, work out critical details, then move to less critical details.