5:43 p.m. on October 1, 2011 (EDT)
Have wife go along and stay at Paradise Lodge. She can tool around the area and will have a great time even taking short hikes along the Wonderland Trail while you are slogging on snow. She will be among the first to know whether to call your insurance agent or not.
RMI is a good, competent guide service. Take advantage of a two day mountaineering course they offer before the climb. Well worth the time and the $$.
40 years old is probably associated with a few more pounds and less activity than when he was 20. Would be a good idea to spend the next 6 months getting toward the best shape the two of you have ever been in. Given that you have good weather, it is simply a very long slog uphill for 20+ hours. Depending upon how many continuous hours you can stay on a gym's stair stepper, the more fit you are the more you will enjoy the trip. The summit day starts right around midnight and you return to Paradise Parking lot around 6 PM. You get a 1 hour break on top.
Other than the info package RMI will send you, a few places to look for guidance on what you should be planning to do every day between now and then is at:
http://www.alpineascents.com/denali-train.asp
Even tho it isn't a Denali level climb, you get the idea.. this is a good guideline.
If you haven't been jogging lately you should check out the walk/jog part of:
http://www.exrx.net/Beginning.html
If either of you are over weight, don't mess around, you should check in with the staff at a competent gym. They will put you on a heavy lifting program with 6-8 meals a day that are higher protein, lower fat and medium carbohydrates. AND lots and lots of water. You will be surprised that your diet is a good quantity of food to maintain the work out program.
And then some general thoughts.
http://sportsmedicine.about.com/od/sampleworkouts/a/WorkoutMistakes.htm
You might toss in an extra wooly jumper as well...just in case.
Another option would be end of July, Mt Whitney from the west (back) side. Leave from just south of the portal at Horseshoe Meadows over Army Pass, to the peak the 4th day and exit via 13,200' Forester pass and finally out over Kearsarge Pass down to Onion Valley on the 7th day. 50 miles (about, not counting the day hike of lower 49's highest peak) of some of the most spectacular scenery in the US. [You can skim off two days if you exit over Shepherd Pass to the same road Onion Valley is on just outside of Independence CA]