Trailfinders every time for a trip like this.
Please do not rely on TripAdvisor but invest in a decent guidebook to make sure you don’t miss anything you are particularly interested in, be it place, attraction, activity, scenic route, etc.
Then, once you know your routes, call Trailfinders and they will put together a package after establishing stopovers, etc. Another advantage is their ‘buying power’ can sometimes result in other advantages such as room upgrades in large cities, allocated seats on flights, etc.
The agents are well trained and thorough, usually with expert knowledge of the destinations they specialise in.
Another advantage is you have a certain additional protection if there is a delay or problem with your travel plans than if you were booking things separately via Expedia or similar booking sites.