Yeah, so when i mentioned it was little too quick i had frankenstein-ed it together for the test run.

But it worked.
So i punched the rest of holes in the bottom for a Charge/Run switch, a female JST charge port, and ESC switch.
I'm going to be keeping almost everything mounted over in the Left side of tractor because the front wheel locating bosses were on that side. This way to open it: roll to left, pull the 2 screws (that were originally rivets), lift right half up, undo 2 connectors and the halves seperate.
Ordering the wrong cells probably was a good thing, i was able to build up a 5 cell pack that fits in the other half of hood without much trimming. It's only like 650 mAh instead of 1500mAh i wanted, but not like i'm racing.
Mounted a pilot light to the dash, it just plugs into an RX open channel.
I had considered trailering the battery, but really wanted to be able to change equipment, all i have right now is a 4-gang disk. Plus like you said, there wasn't much using Hydro back then.