It's a plus that it is Honda Certified.
... look at the Lifetime miles per gallon ...
I for one agree and as for the LTMG, that it can be changed is true but have a look at it anyway - it may not have been changed.
Also, look for the "little things"; i.e., was the previous owner a smoker? Start the radio and see what "music" channels were selected - rock and roll? Hard core "drug culture music" or classical. These will tell you something about the previous owner(s) as well.
Is there a written warranty coming with the "Honda Certified" vehicle? Whatever the salesman tells you, if it's of interest to you, confirm it in WRITING. If he/she/they won't, don't buy but again, if it's Honda Certified odds are there may be a good deal (price???) there for you.
Hope this helps.
Fred / Proud Owner of "The Silver Bullet"