Raspbian Jessie custom GUI

[Coopler]

Okay so I have a couple questions, and my Googling skills are failing me simply because I don't know enough to even know what to search for.

This is my first pi project, and I'm fairly new to Linux and Python. The end goal is a car computer but I'm doing it piecewise as I can. My current hang up is this: I'm using Raspbian Jessie so I can hopefully use some features from Bluez 5 with AVCRP control, and I eventually want to make my own GUI that the pi boots straight to and just has a few simple buttons. It's an older Pi too, if that makes a difference.

1) Is this possible/practical?
2) Where do I start in doing this? I couldn't get the pi to boot to the command line in Jessie without uninstalling lightDM, but from the brief glance I gave it, I think I'll need lightDM to make my own GUI to boot to. When I try making it auto-login by changing /etc/lightdm/lightdm.conf it still goes straight to the GUI login (with the Debian 8 background). Is that part of the GUI and not the Pi logging in? If so, how do I go about replacing the desktop GUI from Debain/Raspbian with my own?

I'm not expecting detailed solutions (though those would be awesome), but at least point me in the right direction? I'm really pretty lost in Linux and looking for at least a point in the right direction.

[ghans]

Since you have very specific needs , you will propably have to start from scratch and won't be able to use an existing solution.
This is a programming task , and in my opinion it doesn't even matter which graphics toolkit you use , just that you know how to program.

If you are comfortable with HTML , there might be an interesting "way out" of this programming problem : Use the excellent
"kweb" browser of forum member gkreidl - reading the manual is a must , though.

Autostarting your GUI or "App" is a minor problem which can be easily solved later.

ghans