How do i store and rotate and carb

Ok, I have a 2 tap kegeraror that will fit 3 corneys. I have an old fridge that will fit maybe 2 fermenters or one fermenter and one corney. I want to always drink my own beer. I am starting to brew a batch a week for the next 4 weeks. So, how do I carbonate one keg while pouring another 2? Should I set it to30 psi then unhook it and let it sit? If I do that does it need to be kept cold? Should I use priming sugar in the kegs and rotate them in? I am trying to figure out how I am going to handle all the beer I am going to be making.

Go ahead and prime the kegs not is you kegerator use half the amount of sugar that you use for bottles. Then when you need to swap out the keg it is ready to go.

^^ +1

I have the same 2 tap kegerator set-up as you and I am using priming sugar to carb one or two kegs outside the fridge. Works great and keeps options available all the time.

Personally, I would buy another CO2 tank and regulator. You can get refurbished 10# tanks on ebay for <$40 and another regulator for $40.
Sure, it costs more, but you don't have to deal with exciting up the yeasts again.