You may face some other issues like rust in the gas tank so before you crank it over I'd drain the tank and blow out the fuel lines with compressed air then add a fuel filter in line that you may need to replace once or twice.
If you rebuild the carb and you'll likely need to the last thing you want is a bunch of junk from the gas tank plugging it up and messing up your fuel pump.
As for the engine internals,there is likely some rust inside and it may even be ruined but lets just assume it's light surface rust for now and hope it'll clean up without a rebuild.
Do not try to turn it yet!
I'd pull the carb off and pour a couple quarts of diesel down the intake then pull the spark plugs out and fill each cylinder with diesel till it runs out.
Put the plugs back in finger tight and stuff a rag in the intake and let it sit for a week and soak.
Diesel will dissolve rust and loosen up stuck parts like valves,lifters,rings etc and it will give some lubrication when you start to turn it over.
After a week or so pull the plugs out again and see if it will turn by hand,if it spins easy your ready for the next step,if it doesn't turn easy but does move a little work it back and forth till it starts to break loose and crank it a half turn then fill with diesel again like before and let it soak some more.
That will get the parts missed the first time now that it's rotated 180 degs.
Once you have it spinning easy enough by hand hook up a battery and spin it a few times to blow the diesel out of the cylinders then give it an oil change and some fresh gas preferably with a freshened up carb and fire it up.
If it starts don't rev it anymore than needed to keep in running,tap the gas gently,just enough to keep it from dieing and let it run for a bit.
She'll probably smoke like hell for a few minutes but should start to clear up after a bit as she warms up and the diesel burns off.
It may make some lifter noise till it gets some oil pressure built up.
Use a light weight oil that will flow quickly in a cold engine and don't buy expensive stuff because you'll want to dump it out and change the filter and oil again after you've started it a few times but before you drive it the first time.
All that rust etc in the motor is going to be in the oil and you want as much as possible out of there before you drive it.
Better figure on a fresh set of spark plugs after all that too.
Other thoughts,blow out the brake lines and add fresh fluid then do a brake bleed job.
If she's been sitting out in the weather you may need to rebuild the brakes completely,brakes are pretty important so make sure they work right before you try to drive her 'eh.
Good luck,hope she comes back to life for you without too much trouble.
I've brought back a couple pretty stuck engines this way that ran pretty fair afterward.
Had a 396 that wouldn't budge at first but it came back to life.