Do you do pinterest? I'm an old house person, living in a 20 year old box. We sold a beautiful cottage we'd renovated from the floor up (proper rebuild stripped back to three walls and bare walls, wired, plumbed, plastered, fitted etc).we had the gardens hard landscaped, overhauled the orchard and terraced it, levelled large sections of back garden, removed some trees and planted lots more. I thought we'd be there for life.
Our box is 1/3 size, tiny town garden, in town rather than beautiful countryside, characterless by design.
BUT...its getting to be ours. We've landscaped the garden and fitted an amazing amount in with careful design. The chickens are in a small corner pen rather than a 1/4 acre one (but we've three rather than lots), the children have a climbing frame that doubles as a pergola, a play cottage with slide from the upper floor and we have seating and eating areas. Inside we've fitted a country style hand made kitchen off ebay and its really nice, we've knocked the kitchen partially through to dining room to open up the space, rewired, redone bathroom and ensuite, divided a bedroom so the children each have their own cosy space. We have got out eldest into specialist education and our youngest is getting support. Family are for the first time in my adult life in walking distance.
I did get a bit of post move depression when it felt like we had all the negatives and work (cost) ahead of us. 17 months now since we moved in and its finally feeling like a home, not just a practical space to live in.
Pinterest helped me enormously with getting the homely feel. I created boards for each room and just pinned everything I liked on them. I knew from the images i'd repeatedly selected that i really wanted a painted dresser and throws on my furniture in my lounge, i knew the colour scheme I wanted to achieve. Budget was very tight but I managed to eBay our old furniture and buy replacements, again from ebay and charity shops, for the same amounts so it was an effort cost rather than financial one.
It really does sound that financially you are going to be in a strong position if the market is improving in your area, the gap between your bigger house and the smaller cottage will grow which can only leave you with more money for making it just the way you want/ having less debt. Play the long game.