In many cases, PCs were peripatetic, where not simply garaged somewhere abstract between weekly dungeon delves, so the issue rarely arose. In the earliest days, some characters had (off-screen) castles - something spend six figure fortunes on. My MU, Ororo, was planning to create a demi-plane, a cottage in an eternally summer garden in a small valley magically hidden in the middle of a howling snowy waste, the way in being through a gate in the wastes, but the campaign folded before she could organise the magical wherewithal. It would have had home comforts, defence in depth, and, most importantly, significant swank value.
The one home base that had significant time invested in — both design and play - was Doc Savage's lab in the London Watch Champions campaign, but despite the fact that I did the job of putting it into a CAD system, the passage of the years has eroded memory of the design process. In that game I did have a PC with a defined pied à terre; Pushover had a flat [never detailed] in the block containing the Women's Centre where she worked, but having been developed as a character, decided that the macho super-hero thing wasn't for her and faded out of play. [I'm getting my revenge now — an alternate version of her is co-starring in my latest fiction, and she's going to have to deal with being faced with the problem of saving the world this time.]
There was a home base in the last AD&D2 game, a castle, but as that was the holding of the NPC Baron for whom the PCs worked as elite forces, it was a given, rather than being chosen. In the paratime/60's spy game, we were also eventually given a base, an alternative where a paratime capable civilisation had been wiped out. The most involved base-like stories with off-beat design criteria would have come from the local Ars Magica saga ( Saxum Caribetum ), where founding the covenant took most of the first realtime year's play, and it took a resolving a lot of squabbling about the library before construction even began.