Main panel on the complete opposite side of the house of sub panel. Transfer switch wanted.

[solardiff]

Hello!

I am curious about my current situation with how my house is laid out and where the panels are for hooking up a transfer switch to power my subpanel and maybe my mains panel. Currently, there is a generator plug-in on the mains panel and I have to use the manual interlock to shut off the mains, switch the generator breaker, and then turn on each individual item.

I want to get into solar (mostly DIY given codes and permits), and I am having an electrician come out to discuss options for transfer switches (just wanted to get opinions from this forum before they come out). I'm a bit worried that the mains panel is on the complete opposite side of the house where the garage and sub-panel are. Is it possible to have a transfer switch to be able to power on my AC and well pump and other large loads that are off the main panel in addition to the sub panel? Or am I stuck on powering lower critical loads from the subpanel if I want all my batteries and inverters in the garage?

I attached some files so hopefully it helps. Thank you!