We ( family of 6 ) are planning to tour the Canadian Rockies in July 2010 and on the last leg of tour we want to know the best
route to take from Kamloops to Seattle.
Is it worth while to travel via Cache Creek / Ashcroft / Lytton to Hope ( scenery ? )
or is it best to keep on the 5A route via Merrit to Hope.
Also would like to know if there is a border post near Huntingdon / Sumas where we can
enter the United States again on route to Seattle, or do we have to go via Vancouver?
Your suggestions would be hightly appreciated.

The route via Cache Creek and the Fraser Canyon (Trans-Canada) is quite scenic, but it is will take you somewhat longer than Hwy 5 (Coquihalla Hwy) through Merritt. The Coquihalla is a four-lane toll road, while the Trans-Canada is mostly a two lane highway with frequent passing lanes. It is also a shorter route between Kamloops and Hope than the Trans-Canada.

There is indeed a border crossing point at Huntingdon/Sumas so you don't have to go via Vancouver.

Another very easy border crossing is Aldergrove/Lynden. Take 264th st exit (Hwy 13) from Hwy 1. Although it is further west than Huntingdon/Sumas it is a direct route to I5 coming in just north of Bellingham.

Thanks for the help,really appreciate it!