The slide out interfering with the travel of the front seats is a common complaint with many motor home manufactures.
When internet shopping, an easy visual indicator is to note the transition wall coming straight out sideways, then the slide out being right up close to that wall. Here is one example.
To avoid the condition, seek a motor home with an angled transition wall that is more aerodynamic. It places the slide out significantly farther behind the driver seat as seen here.
TMJ1642,
If your issue is serious enough, seek out a driver seat with a thin backrest. They may be marketed as "Sport Seats". Most RV seats have exceptionally plush back rests which reduce travel to an already tight condition. A thin backrest may increase seat travel by as much as 4" depending on how plush your current back rest is.