Does the car have a fuel economy gauge? Making each trip a game to beat your high score is always one of the first steps to squeezing more out of each tank. The quickest & biggest gains come from adjusting your driving style with instant feedback.
High speed is one of the biggest things working against you, but I'm sure you know that already. See:
http://ecomodder.com/forum/showthrea...you-15182.html
FYI: here's what others are accomplishing with their 4-cylinder Camrys:
EcoModder Fleet list - EcoModder.com
And I wouldn't read too much into the MPG of that return trip vs. the trip out. Many variables could have significantly skewed the results (eg: headwind in one direction, tailwind in the other; traffic density).
Welcome to the forum!