I agree with the idea of making a swath of grass/path following your existing shapes, and gardening the rest of the space. I also agree with a brick or stone edging. Both those things worked very well for me. I don't have a sidewalk on the outer edge; my constraint is a deep ditch, which forms the outer limit of the garden space. I like the relatively straight line it makes as the edge. You don't have to do it all at once - start with Yard Advisor's corner bed. Get that set up and planted and keep thinking about the rest. Over the following year - or two or three..., you can gradually extend the corner bed towards the house bed, and along the sidewalk. If you do it gradually, it won't feel like such a big change/lot of work but rather like a natural evolution for the space. That's the way I did mine. Initially, I created a big bed in front and a narrow one along the driveway. A couple of years later, a small one was added behind the driveway border where the driveway curves plus another small bed was added in the N&E corner of the property. After a couple of years it was clear that all of those needed to be made more coherent and connected. So I measured a consistent distance from the edge of the main, large bed to eastablish the ribbon of grassy path that ties it all together. The ditch limited the outer ('moat') bed to a very narrow shape but the brick edge gives it more definition and it all works quite well I think. I think something similar would work well for you as shown in Yard Advisors drawing. Here is a link that might be useful:

Outsmarting the tree rats (squirrels) around my house is a full time job. This past spring I hit on a new idea. When I plant a container I invert an empty wire hanging basket over the container and the plant gets sun and can be watered but the squirrels can't dig in it. Another idea: I bring in a lot of plants to "over winter" under lights in my garage. I have so many that it is hard to reach my hand under the lights (4 shop lights) to the middle for watering. So I bought a pump sprayer with a long wand and it works great! In late winter I add a little liquid Dawn detergent, few drops, to each gallon of water and not only does the soil get wet easier but the worms that are waiting to hatch into distructive pets just don't hatch. Don't know what it costs me to run those four shop lights all winter but I don't care. It is a small price to pay to be able to "garden" every weekend in the garage. Many people have mentioned that they mark their outdoor plants with a "permanent Sharpie". In my experience there isn't a "permanent Sharpie", they all fade and quickly too. A grease pencil/china marker or expensive "no fade" garden center marker are the only markers I have found that won't disappoint you by fading. Eight years ago I decided to learn about gardening so I tapped into my local library. I checked out nearly every book they had on gardening and learned so much. The Gardenweb forums are also a wealth of information and entertainment. There is always something new to learn and I appreciate all of you who take the time to write in your ideas. One last idea from me...I keep a small notebook on my computer table and jot down any idea I find that's new and I will want to try. Little pieces of paper get lost but I always know where my notebook is and also use it when I order "on line" so I will remember the name of the company and the order date. Tina or Trowelgal

Here's a solution that worked for us. We lengthened the rails so that the longer queen mattress would fit between the head and foot boards. Then we just laid 2 x 4 crosspieces across the top of the rails to hold the mattress. By opting not to mess with the width of the bed, we didn't have to worry about the connecting system. Granted the mattress is a bit wider than the head and foot boards, but it's not really very noticeable. It does raise the height of the mattresses by quite a bit, but I like a high bed, so this wasn't a drawback to me.

I think drapery tape or most any other fabric would stretch and sag in the middle.   If I was tackling this, I might put a casing on the fabric and slip in a dowel. Then I would screw in probably 4 cup hooks under the bottom rail, each end and between the supports. Then cut a slot like a buttonhole matching up with the hooks and support the dowel on the hooks. I don't think you would need to finish the edges of the cuts because they would  be hidden and shouldn't get any tension. If you try this, be sure to drill holes for the hooks because the hooks are usually not very strong and that wood is going to be hard.  Lace isn't my style so I might try a plain color boring fabric...at my house it would be whatever I found in my stash until I decided whether the approach was a winner.