Hi ,,I am in need of some advice for driving routes from Erie Pa to Las Vegas. My wife and I have a very strong dislike of driving in the mountains, so would anyone know of best routes for us so we can avoid the mountains as much as posibble. If we cant avoid the hills when do these roads start getting snow covered?

You are going to have to brave some mountains. The least mountainous route would require dropping down to Oklahoma and Texas and southern Arizona to Phoenix and on to Las Vegas but that adds 400-500 miles to your trip.

Next best would probably be I-80 through Salt Lake.

When are you doing this that snow is a possibility?
The I70 interstate through Colorado is a HUGE highway, does not have dropoffs and is not a difficult drive.
Snow can happen at almost ANY time from October so you'll just have to watch for weather fronts.

If you want a slightly more southern route, take I-90 to I-271 to I-71 to I-70 then drop down on I-44 to I-40 to route 93 and up to Vegas. You need to check the weather in any case as you could hit snow. This keeps you on interstates until you hit 93 near Kingman, AZ, so there are no skinny mountain roads, and the roads would not be snow covered unless it is actually snowing. There are also plenty of places to hop off and stay if the weather does get bad.

Once you get to I-40 there are plenty of places to visit close to the route, like Petrified Forrest/Painted desert NP and Grand Canyon.