Nice! Sounds like you are on the right track. I went the DIY route for the lithium batteries and save a lot of cash.

My favorite thing about using a DC-DC is it allows you to move away from a 12 volt system.

I find very little need to stay 12v native, especially if you want to move into a lithium setup. The most power dense cells available (like 18650) have a voltage that falls perfectly into a 24v range, so that's what I have been using.

I have a traditional dual battery, but I also run a portable 24v setup in my 4Runner using the Victron Orion 12v to 24v DC-DC, but have plans to build it into the little cubby space above the passenger rear wheel well.

Lots of gear is already 24v compatible, most fridges are 12/24v, most LED lighting works off 24v, Viair and ARB both make 24v versions of air compressors, better inverter choices, more efficient, and smaller cabling requirements for the same power.

I know it's a little odd to move away from 12v but i've tried it both ways and it's worked out well.