21 mile trek.

Ok so basically I plan to move whiskey closer to home next week for about a month or two for the border ride-outs and gala days. However we don't have a horse box yet and rather than ask my friends about borrowing theirs I feel it would do us good to walk the distance.
I have done the whole google maps thing and got an average walking time estimate of about 6.50 hours (human walking pace). However I think that is sticking to the main busier roads, I plan to go the quiet route.
The farthest we've ever traveled by ourselves in one day has been 16 miles. Also I am not too sure of the road so it would be nice if you guys could help me decide on what things to take.
I plan on taking a map, so I make sure I don't wander off the wrong way.
My mobile phone, and some energy bars and water.
Is there anything I should take for whiskey?

We frequently do 20 mile rides. With a nice lunch stop, You can easily do that in 8 hours. Make sure the horse has access to water along the way. Especially if it is hot. Pick a lunch spot where your horse can graze a little and drink. Even if you just have somebody met you with some hay and a bucket of water. It's pretty easy for a working horse to go thru 20 gals of water in a day, So bring more than just a few gallons

Enjoy your ride. It's not a big deal. Wild mustangs travel 20 miles a day with their babies just to go get water in the desert

Thank you painted horse, that was the re-assurance I needed, i'll speak to my step dad about meeting me half way with water and hay for whiskey :)

Well I can honestly say my girlie has done me proud. She was a complete saint through the whole journey. She never batted an eyelid at any heavy traffic we met (although there was a terrifying log at the side of the road at one point).
She has now been re-united with her old pasture mate and is very happy.
Also I think it's safe to say we are both exhausted! (or at least I am).

The journey took roughly 5 and a half hours.

Congrats!