BE$T bang for your buck home improvement for home sale

Just had an appraiser/inspector out to my place today, as we are looking at a refinance to get way better rates and some cash out to finish my shop with concrete heat and power. The guy said our area is a buzz of business real estate wise. I get random calls from realtors asking if I'm interested in selling or know anyone else with acreage selling. But I repainted my house inside and out this year, built a closet in a room downstairs with a bathroom and fireplace. The guy was real pleased to see that as he said it added a ton of value with an additional bedroom. A large master bedroom at that. He said I should have added a door to a room that is a catchall between the living room and deck. As its got a closet, and two exits. I would have then had a 5 bedroom 2 full bath 2600+ sqf home with finished daylight basement. If I ever sell I'll hang a door there then. I'm hoping as I bought it as a bank repo 15 years ago for $188k that I get a 500k appraisal. With a 36x48 shop, a few equipment sheds and fully fenced property, triple pane vinyl windows and sliding doors, flooring replaced, new roof, well and septic upgraded, fingers crossed it goes good. My wife has been a nervous mess, painting everyday for 3 weeks. She is very good at it, I was a painter for 15 years and taught her well.