go visit https://diyrobocars.com/
for some information on building a donkey car or other suggested rovers there.
Then look at http://www.bot-thoughts.com/
at his previous posts about his rover databus. Those will hopefully get you started.
Sensors go from the very simple, to scanning lidar units and visual cameras like the OpenMV M7 but don't worry about those right now.
Figure out how to send pwm pulses, and learn how to drive it around a bit just using that.
Then add an IMU of some sort and try to keep the bot moving forward in a straight line.
Then add turning of corners.. (like 90 degrees)
Now add an encoder and drive a set amount and then turn.
Get your bot to do "squares". (Drive X feet straight.. turn 90 degrees.. Drive X feet straight turn 90 degrees.. repeat). If you can do this for a decent amount of time (say 2 or 3 minutes) then your base platform is doing pretty well... it should stay relatively straight. This will be a good measurement of your encoder quality, and your imu quality.
If you make it this far, I suggest pure pursuit as a navigation strategy. It's not the only one out there, but there is information out there and even code to implement it out there.
Then you can worry about other sensors.
Those would be..
Scanning Lidars are certainly starting to make an appearance, if if done right can be very useful. Very few are using these effectively, and range is greatly reduced in sun.
A single ultrasonic, or lidar unit like a lidarlite can also take you very far.
Even something as simple as a bumper sensor, and smart algorithm can get you pretty very even.
Or just try to run everything over like I do.
If you want more information send me a private message with your email and I can give you more information.