Cross Country flight: what do I have to consider concerning radio communications? I'm tasked with developing part of a cross country flight plan to cap off my ground school class. Among my group, I am handling the radio communications and regulations. However, I was not provided further details, and came here to gain a greater understanding of what I need to accomplish. Specifically, the trip is to fly from Aspen, fly by Capital Peak for the view, and then land in DIA (KBDU-KASE-KDEN). 

As far a radio communications go, I imagine I need the frequency of each of the listed airports, but is there anything else I need to consider? 

Edit: Further Information:

I'm flying N370SP, a Cessna 172S Skyhawk SP. I pick up friends (190, #320) and luggage (35, #60).
There are three categories of radio communication to deal for each leg of a flight:


arrival and departure airport: tower/CTAF, ATIS/ASOS/AWOS, Ground/Clearance Delivery
En route ATC: arrival/departure, center
En route weather and information: Flight Service, Flightwatch, HIWAS, en-route ATIS


You have to decide which of these services you will interact with, and know where to find the frequencies (almost always a chart or the A/FD) and how to contact each of them.