Tires???

That cracking is an indication that your tires are old and should be replaced before you go on your trip. The size is listed on the sidewall. Call around to various tire dealers to see who has that size and how much they are mounted and balanced. Since you are some what pressed for time you may not be able to get the best deal as some tires have to be ordered or they may not have as many as you need.

You could chance the trip, but I would be very leery of doing it. If you get a flat on the road, you will pay dearly for a new tire and to have someone bring it to you, plus you may get damage to the vehicle when the goes flat, they usually shred and pieces are flapping around doing all sorts of damage to the coach.