Your thread illustrates why anyone who will be developing their yard need to first create a PLAN. Not just a plan in their mind, but a master plan committed to paper. A master plan shows how all built elements, including planting, will be organized on the property, though it does not necessarily show how they will be detailed or constructed. It will show the size and placement of hardscape from the bird's eye view. It allows you to add major elements in phases over a lengthy period of time without one thing getting in the way of another, so long as you build in a proper order, i,e., build hardscape of a given area prior to planting of a given area. (I'm defining hardscape as any built thing that is not planting.) There is an order of construction much like building a house: first there must be a foundation, then framing, then wiring and plumbing and then paint and wallpaper, and the order cannot be reversed.

One psychological hurdle I've found people have AGAINST creating a plan is fear of "What if we want to change something later!?" No problem. Amend the plan. Often this amounts to tweaking rather than a full blown reorganization. Since the master plan only shows where an element is located in the yard and its shape and size, often additional drawings are needed at the time of construction, that shows the element from different views and its different details. But these drawings are done just prior to the actual work, not years ahead of time. Even a plan that doesn't show everything in its perfect, final placement is much better than no plan at all.

Creating a master plan begins without needing any creativity at all. One first must create a base plan that shows all major existing elements of the property: lot lines, house footprint, any paver surfaces -- walks, drives, patio -- fencing, tree trunks, utility apparatii, etc. If there are shrubs that will be permanent, one could show their simple outline. It's important to keep the base plan as simple and clean looking as possible, so don't show any extra details or things that are not permanent. No shading, cross-hatching. Usually, it is not necessary to place dimensions on the plan because it is measured and to scale already, meaning that everything will be in correct placement and proportion relative to other things shown on the plan. A person who can use a measuring tape and draw lines is a person capable of drawing a plan. One can either use graph paper, plain paper and drawing tools, or an electronic medium if they have a stylus and touchscreen computer. Example of base plan (the double line is a retaining wall by the house and a mowing strip edging elsewhere.:

Permanent ideas of the master plan are worked out on tracing paper placed over the base plan. An inexperienced person is probably going to need help getting things well organized, so it may take some time to work them out, with some assistance. Or, they always have the option of paying a professional landscape designer to do all these things for them.

It's not difficult to run an underground PVC water line to a far back portion of the yard. On account of the tree you'd need to keep the line near a side lot line and you'd probably want to rent a trencher.

Wow! Thank you for taking the time to write such a detailed response.

Now ... make it happen! :-)