Bassmanbob

I plan to retire in the spring of 2033, and my wife knows the first summer of retirement will be spent cycling the Trans America Bike Trail from Astoria, OR to Yorktown, VA. An extended tour like this has been a dream for me since I was in college. I'll be 68 years-old in 2033 and will hopefully do this with a friend of mine. But if I do this solo, I want to make sure I save enough so it doesn't cut into retirement funds. I want to make sure I have everything saved prior to the tour. I already have the bike, the camping/ cooking equipment, the panniers and the electronics. It's ten years away, so I'm sure I'll have to replace some things before the tour. I just want to make sure I have the funds already set aside for the actual tour, once it starts. Of course I don't know how much inflation will there be between now and 2033, but the estimates below factor in a very vague estimation. Also, my experience is very limited to two short tours that were both three days. I plan to do some more short tours the next ten years, but probably not longer than a few days.

I'm thinking I'd ride approximately 50- 60 miles/day, 5- 6 days a week. This would take me anywhere from 14- 17 weeks to complete the 4,300 mile route at 250 - 300 miles/week.
Cost Estimates:
Food: $50/day x 7days/w x 17w = $5,950 ~ $6,000

Lodging: Camping: $30/n x 5n/w = $150/w
Hotel: $200/n x 2n/w = $400/w
Total/w = $550/w
X 17w = $9,350 total ~ $10,000
Note: I've read there are a number of legal free camping options along the route, but I don't want to count on that. Also: Most inexpensive hotels are not that expensive now, but I don't think I should underestimate the cost for them in ten years.

Bike Maintenance: 1 Chain: $50
4 Tires: $400
4 Brake pads: $100
Miscellaneous : $500
Total: $1,100 ~ $1,100

Clothing: I plan to have family mail me prepackaged items that include new clothing to various locations, but I'm sure there will be some moments I'll have to purchase something not expected. I've allotted $500 for extra clothing. I could also purchase the bike equipment prior to the trip and have that mailed too, but I'll leave the bike expense estimation intact. ~$500

Entertainment: Movies, museums, park fees, etc...
$100/w x 17w = $1,700 ~ $1,700

Total cost during the four month trip ~ $19,300

So what am I forgetting? Are my estimates WAY OFF? Obviously, we can't predict inflation, but would you estimate this in a similar manner?