I hope there's a spare battery in that gear for the electric bike you have there. That looks like a currie tech product. You are going to drain that battery with all that extra weight. www.highpowreredcycles.com
They sell a solar option for charging that won't weigh you down. What I mean bythat isn't that it is light but that the missing weight of the money you won't be carrying with you will make up for its weight. But if you are serious about this, then its something to look into.
Nice set up with the dolly. Look up some ways of attaching it on the internet. Bungies and zip ties are good for to the store and back and they might make it in a bug out or get home situation, but if there are purpose built items or less temporary methods of doing it, then that's a better way of doing it.
Also consider changing the tires on the two wheeler. If you can ge bicycle tires on there, it will roll easier and more stable in turns.
I also just wrote a post about using an entire bicycle as a cargo trailer for a ridden bicycle. If you have two of the same bike, then you have spare parts right behind you and in the case of a catastrophis failure of one, you have another bike to ride. You could even tow a kid trailer behind the towed bike.
If you are going to use a powered bike for this, it might just be better to get one o the two stroke kit motors for bicycles and install it.
You could do this on some electrics and have redundant drives, extra power and extended range. I mentioned this in another post but will repeat it here.
The usual way that the two (or four) stroke motor is mounted on a bike is in the big triangle. Then there's a chain running from the motor to a srpocket on the left hand side of the wheel. The sprocket is usually bolted into the spokes. This is ok but has some problems.
What I am going to do with my set up is attach a sprocket of some size to the spindle of the bottome bracket and drive the cranks with the motor.
That's right, ill be able to use my gearing system in conjunction with the motor.
Not sure if this can be done with all bikes and even if, it requires some modification. One, you will have to find a sprocket to attach to the spindle and figure out how to do that. My idea is to get a left hand rear sprocket for a flip flop hub, and take a metal collar and thread it to accept the sprocket. Have the collar welded carefully to the spindle. Then the sprocket can be put on. Since its a left hand job, it will tighten under drive toruqe.
I will then add some bmx pegs to the seat or chain stays so as to have a place to put my feet and keep my legs out of the way while the motor litterally pedals for me.
This has a couple of advantages, one, I doesn't apply torque directly to the spokes causing possible failure. It uses less chain and the sprocket on the spindle is lighter. It doesn't complicate rear tire changes the way another second sprocket and chain on the left side do.
It allows you to change over a wide range of gears, finding a great balance between speed, power and efficiency.
You probably want to install shorter crank arms (these will be less efficient for pedaling) so that you have less chance of getting your legs whacked while riding.
These are things that I am or will be working on.
Will update when I get stuff done.