Regarding engines this info might be helpful...
Coal Engines: 2 types, small and regular one...They're both easy to make and dont take much room so might as well make the regular...It is slightly more efficient and holds more fuel.
Solar Engines: Most people say compact solar engines, but just because it has a higher modular and material cost doesnt mean its better. The ONLY difference between it and a Solar Engine lies in it's placement and energy storage...The compact solars take up side slots instead of the cart's top slot.
Compact solar engine holds 25,000 units, Solar engine holds 800,000.... Even the small solar engine holds 100,000 (but it's less efficient). You don't see this until you've actually installed the thing, and when you set up your cart, just leave it in the sun for a bit to charge up. That gives it a nice battery backup for when it hides under foliage or bad weather / nighttime rolls around.
If you don't use solars, it shouldn't be a logistical nightmare to set up a loop that takes out some wood to make charcoal and pumps it right back in. You can even build that in a small room underneath your cargo manager / distributor so it's out of the way...or if you like the idea of a small hut off to the side with your machinery then that might be interesting too.