I'm not sure where my head went but I'm a little lost in the sauce...
I ripped out all of the existing wiring in my abody only to replace it with a Ron Francis express kit.
Giving that I'm going to go full MSD ignition Whats the proper way to rewire the car relocating the battery in the trunk?
Do I stick with a mopar starter relay?
Do I convert it over to a ford solenoid?
Painless hotshot kit?

Picture and diagrams would be EXTREMELY helpful.

For my battery in trunk installation + MSD, I used all factory wiring except 1) Heavy cable from battery in trunk to starter terminal (1 Ga). 2) Moderately heavy cable from starter terminal to fender relay for charge current and start power (6 Ga) 3) tied ignition switch "run" and "start" together to feed the MSD "run" signal. 4) Frame ground for battery in trunk + dedicated 2 Ga ground cable to front frame and engine block.

Lots of ways to do this... approach above worked for me.

decide if you want the main cable from the trunk battery positive post coming forward to be hot all the time or not. Me I'm OK with that (FT hot) as I use welding cable which has thick insulation which is made for flexing out in the field in use and the cable strands are very fine (same reason) & I secure it firmly at multiple points from front to rear. No danger of shorting out unless you are in a major wreck. going right to the starter large battery stud then a large cable from starter up to the starter relay then everything up front is wired normally. don't scrimp on the gauge as voltage drops will aggravate you (I forget if I used 1/0 or 2/0). if you dont want FT hot then a continuious duty furd type solenoid back by the battery inline in the positive cable then a smaller trigger wire from switched 12V up front back to the solenoid. I'm missing some things but that is my take so far. EDIT on the PT hot, not sure how the right way would be to get the non starter switched 12V power up front with the solenoid cuz I ain't never done it that way working with that solenoid with its mini terminals etc in addition to the main in/out large hot terminals for the starter but others have done it & will likely chime in later

Good deal... I really couldn't care less if there is a full time hot running to the front of the car. I just want to make sure that I get all the other basics right... It sounds like both of you guys are running stock starter relays?

I am. if you run the FT hot cable to the starter lug & a 6 or 8 ga as needed up to the relay then everything else is normal. adequate gauge cable (trunk to front) is critical. I dont even use a furd relay in the trunk. I don't sweat the FT hot & it keeps it simple & just shifts the batt weight rearward.

I wanted to clean up the engine compartment some so I ditched the stock relay setup. I put a Jeep solenoid in the trunk and ran my starter wire from it, then I run another hot up front for the rest of the electrical.

The Jeep starter relay is a ford style relay but it has a ground post that works with the stock neutral safety switch.

Run two separate grounds in the trunk to the body, not just one
Same thing up front, ground the block with at least two good #2 gauge grounds from the frame or body
On the gauge of cable from the main battery feed to the solenoid for feeding the rest of the car, you might want bigger, like 4 or 2 gauge to insure adequate electron flow, especially if it is a street car with lights, sound system and so on

NIce! Do you have a diagram of how you wired everything?