Hello Josh,
On three,.. Jump!
With that equipment, it looks like an easy landing for you, both feet firmly planted.
With all that room, its going to take a looong time to finish. Don't rush anything. Learn what truly makes you happy, and watch out, your brain will lie to your heart! Study each choice, there are many to make, and wrong choices seem to take forever to correct. Set up a simple, temporary carpet central. It will satisfy the itch to run, help you decide on operations, or loops as the base of what you like to do most often when you run them. and it gives you a place, and easy access to power/track to test ideas on. And to just relax and enjoy them between splinters, wire pokes, paint wipes, and swearing at the screwdriver laughing at you from the kitchen.
The 4.5+ on the grade is barely acceptable even with big trains & smaller loads. It was designed with small postwar sets, done in small areas in mind. I have a couple engines that have a two plastic car limit!(one steep grade as a challenge is fun for me) The Legacy should help though, its a constant throttle game in conventional operation without block wiring sections.
What track program is that? Anyrail? A lot of good ones out there, many get used around here. But I think you might want to check out SCARM, a free program (his hobby) used by many here. It has many good features (The best is the 3d view). Files convert to text files, and back for sharing, code can be changed, etc. The author posts here on a regular basis, many people create and share buildings and other "objects". In fact you can grab groupings of objects off any layout file you see. Its stable most often, bugs get fixed, regularly updated, and a growing track & object library.(useful fun for free)
Photos are not discouraged