Good to hear about your Euro and outdoor habits.
I haven't been visiting this forum as much since I got into, or out to, garden railroading. I spend most of my forum time on the http://www.oogardenrailway.co.uk/ site. You might want to go check it out as the guys there all have layouts and are dealing with similar issues.
I'd love to see some pics of your layout if you have any online.
Someone here questioned the use of N scale outdoors... this has tempted me to lay some n scale track on my outdoor layout to see how it works out.
Although my layout started as a place to run my ho european stuff, I'm now looking at getting some American trains in ho scale too.
Sorry about the delay in replying.