Formal clothing: In most cases, you'll probably hold off on purchasing formal clothing until the occasion arises, but easy church outfits could include a few button-down shirts or polos and a couple of pairs of khakis and navy pants.
Khaki button-down long-sleeved or short-sleeved shirts are worn over cotton t-shirts, usually open at the collar (unless the ranger is working in an office, in which case a khaki tie with a brass tie-tack would be appropriate).
This has led to many styles of microfiber shirt lines - from the simple t-shirt offered by Silver Eagle Outfitters to the Hemisphere short-sleeve button-down shirt from TravelSmith, one of the biggest microfiber retailers.
The short sleeved button-down style is also very popular with travelers, especially since some (like Travelsmith's "Trip'r" line) incorporate UV protection and specially-designed pockets useful for tickets and other gear.
Unlike other fabrics, fleece is not usually blended with spandex, so there is no extra "give." If you are unsure of your size, choose a size larger than what you would wear in a button-down shirt style.
Button-down cardigan sweaters for men were a staple of academics - it's the rare portrayal of a male professor in popular culture that doesn't show him wearing a thick cardigan, often while smoking his pipe.
The button-down collar creates a crisper, more professional look, so that if the shirt fits well and is accompanied by a good tie, its inherent casualness or dweebiness is completely offset.
Part of the reason why men's short sleeve dress shirts, even with button-down collars, are still frowned upon in some business circles is because of their use in popular culture.
Standard shirts on offer are usually polo shirts with short or long sleeves, or the classic button-down shirt with extra pockets - neither of which have to be exclusive to boys.
They can be worn with a loose white button-down shirt and then you are decked out for summer but still smart, rather than sloppy, as you are with so many modern styles.