You probably meant 97C, also called the Coquihalla Connector, from Peachland to Merritt?
The road is a great 4 lane divided highway. It initially climbs to higher elevations out of Peachland.
From Merritt you then take 5, The Coquihalla, south to the Fraser Valley and Sumas.
97C and 5 is a great route, lots of climbing and descending but you should have no problems pulling your very nice 15A. 3 has lots of climbing and descending as well as you know.
There is a 97A but it is further north from Peachland. It connects Vernon to Highway 1 at Sicamous.
Driving 97C and 5 south is probably easier to do because of the 4 lane divided freeway type driving as compared to 3. 97C and 5 may be a longer distance but faster drive as you are not slowed by being unable to pass at times and having to pass through a number of small towns on 3. You can also drive slower and enjoy the views without impeding other traffic should you desire.
Another advantage is that you get to see other parts of BC being as you have previously driven 3.