Mind if I ask the brand of the remote start if ya know etc?
This is a little long, but its your thread, so read-up.
Mine is a Viper. This truck was my first install in 2008. I've done a bunch more since then, always with DEI products (all the "snake brands" Viper, Python, etc are DEI), and I've learned a lot.
When the OO had it, he lived in the Rockies and had to plug it in because it was outdoors. He would go out in the single digits and snow in his PJ's to start it, take his shower and get dressed then go out and leave. Because of the EBPV, it wouldn't make power to safely pull onto the Highway in front of his house until it was adequately warmed up. His wife got tired of hearing him ***** so she approached me about putting a R/S in it so he didn't have to go out in the snow twice.
I have a sophisticated Ghost Switch system (I've mentioned it from time to time), which is integrated into the alarm / RKE / Remote Start system. Lots of wires in my truck have been cut, but I know what I'm doing. My installs don't create problems where none existed before I worked on it. The original Viper was fine, but the fobs finally cratered and were more expensive to replace than a new system with updated fobs. I just spliced the new brains wires to the old wires, I left the interfaces to the truck wires untouched. My system is complicated, but has functioned flawlessly for 12 years.
There are stand-alone Remote Starts that aren't too complicated to install. I know the wire colors in the truck by memory, and can suggest some install techniques learned by experience that will make it neat and simple. Look at Viper 4001 4003 series. If you go for it, shout out. I'll help you.
This pic is from a few years ago. Note the cluster-fuc of connections in the center of the pic. These are the interfaces to the Ignition switch. I know how to do these much more neatly now. The black box on the right of the pic is the satellite relay for the R/S. Newer equipment has the relays onboard, and are more compact. A lot of the other mass of wiring is for the ghost switch, Pac Brake, and other things. I'd love to clean this up. But it all works.