Thanks Anton, do you really think the difference between Outpost and Trail is negligible on the summit day? It would add 4 miles to summit day hike r/t. I'm really interested in Outpost for the reasons you all have mentioned, but don't want to regret not having done those extra two miles to TC on the 'easy day'.
I don't think you will regret camping at Outpost - it makes the overall experience so much better for several reasons I have mentioned earlier. The populatiry of TC is based on the idea that one should camp as close to the route as possible. This strategy was developed by alpinists who climb challenging technical lines, and it is hardly necessary for your upcoming HIKE on a well-developed trail. To put things into perspective: lots of folks in their 60s and 70s do this hike as a day trip ... I bet even Bob can do it :)) Extra 4 miles RT sounds like a burden, but keep in mind that your total distance will be exactly the same and you will have more energy on the summit day because you will hike less miles with a heavy pack the day before and will likely have better rest.
After all, it is your hike and these are just suggestions. Enjoy!