What about a window box, for starters? And maybe a trellis with a climber on the side?

trying to avoid window box installation, unless I could find one I could install myself without too many tools..

Maybe a metal window box. I am trying that next, since the wooden one eventually rotted.

Personally, I’d opt for in ground plantings around the shed. Prime reason is they’d be much less work to maintain. The shed is a permanent installation and in ground plantings would be too. Landscape it as though it’s a mini house & make a nice deep flower bed at the side of it. A vine growing up a lattice would be nice but I’d want to ensure it wasn’t a giant one that would overtake the shed! In your zone & with full afternoon sun, you have lots of choices for a nice mix of evergreens & perennials. I assume the doors swing out & flat against shed - at least the one on the left window side - take that into consideration when choosing plantings for that area. A fanciful weather vane would be cute on the roof & maybe a bird house attached to side?

Planters (or windowboxes) will have to be regularly watered.

It looks to me like the gravel is *under* the shed, so it isn't an issue for anything planted next to the shed. What should be planted there depends on where you are (zone is not a place) and how much work you want to put into it. I'd put in a small perennial border, but that's me.

Pretty shed. I've done a lot of zone 7 container gardening because in ground planting was not an option. I think you should do in ground landscaping here on the long side and to the left on the front side. It will be much, much easier to maintain, you can get good everygreen bones, and have perennials that come back year after year. You can still put a nice planter with annuals on the right side of the door if you wish.

I'd do in ground planting too. Cheaper and far easier to maintain. And I wouldn't do window boxes unless you are ready to water every day and change out displays several times a year.

I would go with ground planting and treat the shed as a permanent fixture in the yard.

If you are going to put wheeled vehicles in the yard you will need some sort of ramp. If the vehicles are small like a light weight mower, you may not need it as you can lift it into the shed. If they are large like a heavy mower or lawn tractor you will need a ramp.

My shed is considerably further from the ground than yours. I use a combinations of earthen ramp to with in about 8" from the floor, and use portable ramps to bridge the gap. The portable ramp consist of 2X6 of about 4' in length. For less that $10 you can buy a 2X8 X8', and cut it in half. This is a lot cheaper and just as effective as the purchase ramp.

Here is a video of something similar to what I have.

https://www.youtube.com/watch?v=BfOE6bDTPrg

Built this way they can be put away, when not in use, and they will not get slippery when wet with snow or rain when they are stored in your shed

I have left my shed open on all four sides so there is good air circulation to keep the area under the shed dry and prevent rot and mildew.

I would love to see cutting out of large shrub bed from side to left side of double doors, a few shrubs, low growing and dwarf tree or something. You can always flower in planters and put in beds later, changing to Shepard Hook hanging planters. But def cut out a bigger bed there on left side. Window box would be pretty. Not much tools needed. Our shelf (metal) was screwed in with 2 screws and the planter box sits on it. So two screws and and I was done.

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I'd still advise against window boxes and definitely against hanging baskets. Unless OP is a dedicated gardener with time to lug water to the far corner of the plot once, or even twice, a day in summer such containers will be hard to maintain. Also a box full of damp soil is heavy. How long have those two screw boxes been up?

If you have the sun, I'd do a climbing rose on a trellis. Pick one that's very hardy for your zone. Window boxes are a pain to maintain.

I also think a metal raised bed would look good.