Sounds like you are on the right track. RPM is most easily read with an interrupt. When the interrupt is triggered, subtract the current time from the previous interrupt's time stamp and then do a little math to convert to RPM. Sometime like:
60,000,000/(time1-time0)=RPM
Analog inputs are easy. You have a 0-5V signal that the ADC translates as 0-1023. For throttle for example, just map 0-1023 to 0-100 (%) and print the results to the LCD screen.