Thanks for the replies guy and I appreciate the input. I am going to try and hit on all the topics that you spoke about and let you know more about how I was thinking about getting them to ride.
Not knowing much about bikes I assumed that a big fat seat would be ideal, I see that is the wrong assumption. I was just going on the assumption bigger is better (or in this case more comfortable). I completely understand where you guys are coming from.
Before my mom had me (25 years ago) she was looking at getting a road bike to do biathlons (she had run in several marathons) but she got pregnant with me and quit (she never got the bike). So I know if she ended up getting a good bike she would really enjoy getting back into it. She road wal-mart bikes before she was looking into getting a more expensive bike, so she doesn't know what it is like to get a good one.
My dad on the other hand is captain of the La-Z-Boy, now that he is retired (less than 6 months ago). My mom is getting sick of him just sitting around the house (he goes fishing and stuff but he still is sitting and not getting a lot of exercise). My mom made him start walking with her about 2-4mi a day, a few months ago and he has lost close to 30lbs over the course of 4ish months. He gets bored with it and only goes because my mom nags the hell out of him to go.
He is the main reason why I suggested the big fat seat. I know if it is comfortable for him, he will have more fun, and enjoy doing it. Which also means he would be more willing to go more often.
My mom may get more into it then my dad but I know this would be no more than a casual thing for my dad. A few times a week just like the walking.
I have made the suggestion to them to go look around at the bike store and to check things out (I can't go with them as they don't live near me) but they haven't done it yet.
Thanks for all the input. I really appreciate it.
On a side note I got my bike after I got off of work today and LOVE it. Road about 3 miles (was getting dark) and felt some burning in my legs (I am out of shape haha). They had to take the front wheel off to get it in my car and I was nervous about putting it back on but it was EASY. Took me about 5 min tops to get it put back on. Going to post some pictures in the Mountain bike forum in a bit.