Ryan are you looking for something to build, something that’s turn key or something in between?
With growing kids I’d personally be looking at 57 and up Mopars, 58 and up GMs and 59 and up Ford products. Those were the years that interiors and trunks really started getting roomy. With all that room there are a lot more options for more modern (comfortable) front seating upgrades.
From a mechanical aspect the frames are usually suitable as is. The front suspensions are easily upgraded with a rebuild, disc brake conversion and sway bar addition. The engine bays are also decent sized and engine and transmission swaps are pretty much bolt in. From firsthand experience with a little tweaking these cars make fantastic highway cruisers and are also suitable as grocery getteres.
Just my opinion but the 1960 Dodge, GM and Ford 4 dr Hardtops all had some really neat designs.

