Air conditioning interlocked subpanel?

I have a somewhat large Christmas lighting display and I am running into power issues with circuits breakers tripping as a result of the way my circuits are tied together. All my garage outlets are also tied to all my outdoor outlets and I only have 15A available. As it is, my chest freezer is in the garage and when my Christmas lights are on and the freezer compressor kicks on, the circuit trips. My solution is this: I want to use all the power that is available for my air conditioning circuit since I don't use it this time of year. Can I use this available winter power by adding some sort of interlocked subpanel wherein I cannot use both the air conditioner and the soon to be added lighting circuits at the same time?:helpme 2:

 

Your air conditioner runs on straight 240 volts and does not have a neutral needed for a 120 volt circuit. Also general purpose receptacles cannot be on circuits greater than 20 amps.

 

The better answer is to have a new 15A circuit installed to your breaker panel with one or more receptacles outside or easily accessible from outside.

It's can be DIY project if you're up for learning the details, or it's probably an easy project for an electrician. It would be a great time to add an automatic timer too if you wanted!

 

I would think the quickest and easiest thing to do would be to install a new circuit to the freezer to get that load off the existing circuit.