Hi Brent, You sound like me. About a year and a half ago I too decided to build a layout in my basement for use by my grandchildren. I did'nt have much experience, probably a lot less than you do, I went ahead and bought two ready to run Lionel sets, and built an 8 X 12 table in my basement. Those starter sets came with fastrack and it seemed light years ahead of the old O-27 track that I remembered as a kid. So with my giant table I started buying more track, first I added a bunch of 048, next came a bunch of 060, and then I decided that I could expand the table to 8 1/2 X 15.
after my expansion I went and bought a bunch of 072. By the time I was done I had switches purchased in each size 036, 048,060 and 072. I was running connected loops in 060 & 072 outside of a 9 X 5 layout which was complete with trestles, bridges and reversing loops. Yes it kept getting bigger and bigger, but the outside loops just went around in a circle, and I along with my grandchildren, who regularly play with I Pads and the like were less than thrilled. I mean can you imagine going from the computer age with all the graphics, action and adventures to watching a train go around in a circle. Thank god I had the inside layout at least it had some sidings trestles etc.
After a while I started to think that there must be something more and while looking through an Atlas layout book I realized something, my first epiphany, if I didn't spend so much time putting in larger rails I could get a lot more action, in a lot less space, and after all I was probably never going to have engines or rolling stock that required 072 curves anyway.
That table in the center of one corner of my basement was also another problem! I could not take over the whole basement for electric trains, and the grandchildren would be getting older. If I pads could distract them what was going to happen when Girls, cars, and hormones came along? Egad! I then read two of the permanent posts at the top of this subject, one of them says Please read this first, the other is a welcome from Ross Custom switches.
With tape measure in hand I revisited the basement to find that the corner of the house I was using for the trains was 13 X 23 and If I took down the giant table in the center of that space and rebuilt it going around the outside of the room instead.... BANG a lightening bolt and epiphany number 2.
The next thing that came along was SCARM a free design software for trains. I don't know if it's the best thing out there but I find it to be pretty good, it is the only such software that I have used. Now I will be dismantling the giant table in the middle of the room, and oh yeah I decided to change track types, although I have not made up my mind on which one I will go with I think that Ross probably has the best switches. That statement is not from experience mind you but rather just from reading these forums. The long and the short of it is see whats out there, find out what all of these very experienced model train people on this forum have to say, read the permanent posts at the top of this section, do your research, and plan, plan, plan. For the time being enjoy your 8 X 12 layout, but keep in mind it may be a temporary thing for alot of reasons. Welcome back. Rich