A year ago we purchased a Georgian cottage that was last butchered renovated in the mid 1960s and had been owned by the late vendor since 1970. Sadly, the only hint that it was ever a Georgian property is the facade/front door. Every trace of character internally - including all doors, architraves, skirting - had annoyingly long gone.
Like you @Dominey we love period houses and eclectic, characterful interiors. Our previous houses have all been old, interesting ones, although I admit a lot of the character came from our stuff which is very much maximalist!
We immediately set about injecting the lost character by ripping out the horrid flat doors and replacing with reclaimed versions found on eBay/marketplace. Skirting and architrave will come a bit later. In one room we discovered lovely Georgian floorboards beneath layers of carpet, underlay and hardboard. Unfortunately we also found rotten joists - something you won't have to contend with! More fortunately we don't have ugly plastic windows as we're in a conservation area.
We've removed a hideous fireplace and replaced it with a more appropriate surround and wood burner. Everywhere is getting a spruce with period paint colours in a chalky finish. In the kitchen (relocated to the old living room) we're fitting a mix of original 1960s cabinets and some in-frame ones found on eBay, all painted in characterful Pompadour by Edward Bulmer.
Obviously our eclectic taste in furniture and 'stuff' helps give a period feel, but lighting, curtains/other textiles, lamps and art can definitely make a bland, modern interior feel more cosy and quirky!
I'll add a few before and after pics of our cottage to give a taste of how we're putting the character back.....