Can someone offer me some suggestions for this type of application
If you have (or get) a license then I would look at something like these:
http://www.buytwowayradios.com/products/kenwood/kenwood-tk-3230.aspx
They are small, UHF (work indoors and outdoors), and they have Li-ion batteries so they will last quite a while between charges.
They will only have about one mile range though. If you need something with a bit more reach, I would upgrade to these:
http://www.buytwowayradios.com/products/icom/ic-f4011-41.aspx