Once you apply for a permit to add a new sub-panel and/or transfer switch, you may be forced to bring everything up to code. It depends on your inspector.

Can you flip the existing panel so that it faces the room behind the washing machine (even if its an exterior wall)? That is often a reasonable option when relocating a panel.

There are different type of transfer switches and interlocks for generators , and some are really very simple. They sometimes look like this one https://www.homedepot.com/p/Square-D-Homeline-150-225-Amp-Load-Center-Outdoor-Generator-Interlock-Kit-HOMRBGK2C/203030954 . The general concept is to move the critical circuits over to a new subpanel, and then allow the sub-panel to be fed from either the generator or the main panel, but not both at the same time.

Bruce

Thanks Bruce. I don't think the panel can be flipped. The meter is on the other side of the exterior wall. I did have an electrician look at it this morning. It sounds like I'll need two new items: a main switch and meter mount combo that will also add extra circuits, and a new transfer switch next to that. He had some good ideas about what to leave on the existing panel (which will be on transfer) and what to put on the new circuits. But I'm still waiting to see what the cost estimate will be.

Just to give you some additional figures to work with, the cost of a standard 200 amp panel replacement/upgrade (often referred to as a heavy up) will usually run about $2,000-$2,500.

Bruce

thanks Bruce. My first estimate was $4500 and the second $2250, both by licensed electricians recommended by the AC contractor. Amazing difference.