Thats a beauty 750K. The work ahead you mention is pretty minimal stuff really.
Gas leaking from the carbs. A lot of these bikes, if the fuel petcock is left "on" (up position), they will leak out overnight a bit. So make sure when you're parking it, even if just for a couple hours, turn your petcock to the horizontal position, "off". If they still leak, you probably have to replace your petcock valve since that would mean fuel is still getting through. If it leaks while its running, take the carbs off and make sure the floats and tiny little mechanisms that maintain your fuel level in the bowls are working properly. They're likely stuck if it leaks while running, meaning the level control inside isn't working right and letting too much fuel into the bowl, creating an overflow situation so they leak out.
RPM Surging: If your throttle sticks and this is why your engine is revving, try lubricating your throttle cable. Take the throttle assembly apart and spray in some silicone lubricant spray into both throttle cables. Make sure the lever components etc and the springs are functioning properly on the carb as well. Also, make sure that you have about 1/4" of rotational play when your throttle is a its bottom position (not engaged). This play ensures that you dont risk opening your throttle on the carbs without intentionally twisting the grips.
If your engine rpm surges after start but your throttle isn not being twisted and your throttle play is set right, or after your rev it once quickly but the rpms stay up and it takes time for the rpm's to come down, you likely have a leak in one or more of your carb boots to the intake on your engine. Take some Ether and systematically spray your carb boots that feed to the engine on top and bottom. if you hear the engine spike again in rpm, you know which boot(s) is leaking. These boots are rubber and when rubber gets old it gets rock hard and can crack. If air is getting in past the carbs, that means its leaning out the air/fuel mixture, getting more oxygen and therefore revving up. You can find rubber boots online pretty easily. try
www.cb750supply.com.
Brakes: If your brakes aren't holding even with very little pad left on the shoes, that likely means you have air bubbles in your brakes hydraulic fluid lines. Check your master cylinder first to make sure you have brake fluid in there above the "low" level. If you dont, then you're sucking in air into your brake lines and that will cause a very spongy brake response, or no brake response. Check youtube for a quick "how to" on bleeding brakes. If your brake lines are bled properly already and you have fluid in the master cylinder, you should get friction in the brakes enough to stop it when walking it even with next to no brake pad left.
Again, if thats all you have to get the bike operating properly, you're in good shape.
Listen for any ticking or rattling sounds in the engine its self. Specifically, listed at the top of the engine. If you hear ticking sounds that follow the rpm of the engine, you likely need to set your valve lash (space between cams and rockers). If you hear a rattling sound that gets more intense when revving up you likely need to adjust your timing chain tensioner. If you have a really bad engine vibration, you may need to adjust your balancer chain. Find a good tutorial on youtube for any one of these if you hear/feel any of this and get yourself a good set of feeler gauges. @hackaweek on youtube has an excellent cb750 build that includes all this if you want an excellent documented run down of a cb750.
Good luck!