Hi Westport.
Good luck and enjoy the planing for your layout. I only comment because you have requested same, and hope its of use. One of the mistakes some of us myself included make is to have too much visible track density that may not actually increase the operating potential. Getting the ratio of visible storage sidings to running track is a personal preference and a balancing act.
Not sure what track work you are planning to use, but if you use flexitrack and streamline points rather than set track you will manage to better utilise the available 11ft x 5ft, which is a good size, and also avoid the layout looking too geometric. Also use of curved points at the start of curves can save a lot of space as well as add to visual appeal. Again this is just a personal preference, but consider avoid having all non curved track dead straight. Using track work such as peco streamline code 100 or code 75 also allows for closer track separation and can avoid the set track toy train set look as well as save space.
Best advise I can give is to plan, plan, plan, before cutting, nailing or gluing anything down. I used to make up "dry loose assembled" sections of track and point work to test how they might fit and look before committing to fixing anything down. You can use paper templates, but there is nothing like actual track to give you visual feedback. If you loosely tack down your finished track work before committing to ballasting, you can test operate it and make any changes before permanently fixing it and ballasting. You just never really know how operating options really work until you get to operate and shunt trains and rolling stock. Hope this makes sense and is of constructive help.
Noel