Dealer or Parts Source Request, Midwest I-80

[Larry C Leung]

Hello List,

A friend ('93 100 CSQA) is on a cross-country trip on Interstate 80 and
has lost his gas cap. Looking for either a parts source or dealers along
his
route so that he can replace the gas cap (any problems running without
it,
besides the safety in a crash, bad idle and thrown code?). His route will
carry him through Iowa City, De Moines (Iowa), Omaha and Lincoln, NB,
Cheyenne, WY and finally, Ft Collins, Greely, Denver and Boulder, CO. 
He expects to be in Colorado later in the day tomorrow. Any help here?

TIA!

LL - NY