This isn't EXACTLY what you want, but it is pretty simple:
Most modern Yaesu mobile transceivers, such as the FTM-3200 or FTM-7250 models (others may be similar - refer to the PDF manual for details) have programmable buttons on the microphone keypad. You can program both the P3 and P4 buttons on the mike to go directly to a setup menu item. For example, I can program the P3 key on my FTM-7250 to go directly to setup item #47 which allows me to select a PL tone frequency. I can also program the P4 key to directly to setup item #44 to turn the PL tone on (or off). Prior to dealing with the PL tone, I would key the frequency directly into the VFO using the microphone numeric keys. All of this assumes you are in the VFO mode of the radio (you can switch to VFO mode using the * key on the keypad). Once you have the P3/P4 keys programmed you can do the following:
So, to do this from the keypad, you would perform the following steps:
1) Switch to VFO mode - press the * key on the keypad until the VFO mode appears
2) Key in the frequency you desire via the numeric keys
3) Press the P3 key (programmed to select the desired PL tone) - use up/down buttons to select the tone
4) Press the P4 key (programmed to turn on the tone squelch) - use up/down buttons to select the mode
(Press the P3/P4 keys again to exit each of their respective programming modes.)
That should be it. You can do it all from the microphone keypad once you have the P3 and P4 keys programmed to perform their respective functions.
I know it's not that simple, but with the advent of PL tones being required to access nearly all repeaters nowadays, the steps for selecting those tones are a necessity. Yes, the IC-2AT was simple - it used thumb wheel switches to select the frequency, but it had no PL tone to select, making operating it much simpler. I had an old Heathkit HW-2036A mobile transceiver that had lever switches for the frequency, and it COULD be set up to send PL tones, but I believe that was an add-on. It only allowed for 3 or 4 PL tones to be selected, however - not something that would be useful for today's repeaters.
If you have a Yaesu transceiver I mentioned, try setting up the P3/P4 keys on the microphone. It's somewhat more complicated than just entering a frequency (like an IC-2AT), but you WILL have to deal with PL tones MOST of the time! At least everything is on the microphone and within easy reach.
And, to make all of this happen, you'll need a listing of repeaters along with their PL tones. An ARRL Repeater Directory or their RFinder app on your phone would do the trick!