There can be some significant differences depending on the year and models you're looking at. You can download the brochures for all the model years since 1969.
Previous Model Year Product Information
Some of the late 1990's Adventurers could be either gas or diesel powered. All the braves were gas powered. The last Braves were built in 2004 while the Adventurer is still in production
There's are several pages in each brochure that list the standard and optional features. They include everything from the chassis available to the types of sinks in the bathroom. The Adventurer has a number of standard features that are either optional or not available on the Brave.
Be sure to look at the specifications closely. There are several types of water heaters, ranges, refrigerators, furnaces, etc. While they both will have a water heater the differences may be gas only as opposed to gas/electric, and a pilot light as opposed to electronic ignition.