My layout plans have grown bigger...

[shortliner]

I'd very seriously start by narrowing down those baseboards - and think about keeping your track (and scenery) clean! Reaching across 3 feet of baseboard to clean track at the back, is a sure-fire recipe for damage to scenery and to reach the top left corner is over a 48" reach - unless you are planning to have a walk-all-the-way-around-it layout? - in which case you are going to need another 30" minimum all the way around. If I was doing the design - I'd be running a shelf, maximum 18" deep, around the walls - if necessary on two levels, with switching areas in several places and planning to treat the layout as a series of modules that can be taken apart to work on. I'd spend the next 3 weeks making up a list of givens and druthers - what you MUST have, and what you would LIKE to include - and then the next couple of months looking at track planning books and layout designs on the interwebbything and taking the best bits from several of them. I've been planning layouts for long enough to know that interests change - and that what you think will be a lifetime layout now , sure as hell won't be in 2 to 5 years time, and you'll be ripping it out and carting boards down to the tip........but, RULE !, it is your layout!
PS - do a search for model Railroad track plans on google images or bing images
PPS -" Heart of Georgia" might be worth a look for an idea