Well that is disappointing that the barn and tree are gone. Could you plant some sort of tall evergreen screen? Like several tall narrow trees which would block the unsightly view year round and probably also allow you your sunflower/rose garden too.

Personally, I prefer a trellis to be just about as tall as the vine is expected to grow. It depends on what you like... and what the vine is willing to do. I've seen lovely roses that were a couple stems for the bottom three feet, and then a mass of bloom upwards; and I've seen climbing roses clinging to the top of a fence for 10 or 15 feet. I have clematis that grows to 4 feet and other clematis vines that grow from 6' (in trellis) to 12' (those tall ones are happy covering an arbor). OTOH, ivy will often grow 20+ feet and requires pruning in an attempt to keep it within shorter bounds. Sketch your ideas out, and find out if there is something special your son would like to have. (Sorry, redwood trees don't grow well in Virginia, but a red wood playhouse might appeal.) If you can work something just for him into the plan as well as having him help plant and care for the new stuff, I suspect you both will enjoy the yard more.

I did something similar with my driveway several years ago. It was a very solid base, just had sunk over time till it was pitched towards the house. Would have been a HUGE pain to remove. Just graded it level with mortar and laid pavers over that. It was just a bunch of bags of Type S mortar mix and play sand.. nothing special. I've been happy with the performance through several freezing winters, so yeah - you're on the right track. The expensive part will be the pavers, bricks, or stone. Mortar mix and sand are cheap. Best way to save money on a job that size is to watch Craigslist etc in your area and get some used bricks or pavers to use. You really shouldn't pave with wall bricks but you can get away with them for a few years; if you end up using non-pavement-rated bricks I would definitely use a sand bed so you can replace them later. Again, I wouldn't do that unless you happen to find a bunch of free bricks from someone tearing down a wall..

How would you get a mattress up those stairs? A dresser? Spirals are great to access open lots above, but they totally suck to have for access to a 2nd floor. Your first fireplace pic is probably a electric one or a faux one. You cannot have wood that close to the firebox and it doesn't have a hearth. If the fireplace is as old as you say it is, then you need a chimney sweep out to inspect the flue. It may be damaged, but it is certain to be full of creosote. If the stone wall gets "hot" as you said, that's a BIG RED FLAG. It should only be warm to the touch. Your insurance company will want a report from a flue inspection before deciding if your home can be insured with that fireplace as active. My insurance company required that our fireplace either be redone or decommissioned. We chose to decommission and place candles in it. If you want to cosmetically redo the fireplace, you are looking at 3-5K. If the functionality is compromised and it needs to be rebuilt, then you are looking at another 3-15K, depending on what the damage is and which options you choose. Blocking off the flue and leaving it alone would cost you less than $500.