Help With A First Layout?

[mhampton]

However, eventually I am going to forego using E-Z Track altogether because I want to use FlexTrack on the straights so I can have gentile curves.

E-Z Track only allows Jewish curves?     Sorry, I couldn't resist.  It's Friday and I'm ready for the weekend.

[DoubleDAZ]

However, eventually I am going to forego using E-Z Track altogether because I want to use FlexTrack on the straights so I can have gentile curves.

E-Z Track only allows Jewish curves?     Sorry, I couldn't resist.  It's Friday and I'm ready for the weekend.

Too funny, didn't even see that faux pas.

[rrtreerat]

It looks like it got a little off topic, and I don't think anyone was trying to scare you off with talk of such large radii, any layout, if you've got the space go for as large a set of curves as you can.
Okay; Bachmann's northerns will handle 11.25" radii just fine, I personally have not see one yet that didn't, like any big steam engine though they look 'funny' overhanging these smaller curves but they will handle them.
For double tracking on curves, as pointed out in an earlier post, Bach offers 12.5" to go with their 11.25"  but to help with both of these I strongly recommend using a piece of their 19" radius track sections to transition into and out of all mainline curves, all of your equipment will love you for it be it steam, diesel, or rolling stock.
You'll also want to use multiple power feed points around your layout, because once you've gotten past a simple oval you start to see the power drop off the farther away you get from a single feed point. and for any cross overs between the mains you'll want to be fully insulated electrically.
Hope this helps you out a bit further.