For $500 in Indiana a good hybrid bike with accessories should fit the bill. I'm going to turn 64 next week and I commute 4 miles each way. A wind screen in the winter helps. Since photobucket is charging to share photos my e-mail for fairings and bike stuff is
endlesstailwinds@gmail.com so I can share that way.
Aero mods to the van would be cost effective too.