Colocation can vary a lot from provider to provider.
The facility is one part of the colocation and the Internet connect is usual the second.
The infrastructure of the building you colocate in is important.
Some things to loook for in a facility are Fire Protection, Security, standby power generation, riser space for data, air conditioning and electrical options.
The second part would be your bandwidth or Internet connection.
You can usual get this from the company you are colocating with or
find a secondary provider. It just depends on your wants and needs.
Your bandwidth provider should offer fully redundant, BGP routed Internet
bandwidth or something of that nature. Some providers include remote hands
and some will say they do, but it will be in a very limited manner.
Ask who there up stream providers are. There are different levels or tears of
Colo price will vary greatly depending on where in the world you colo.
Cost as little as $20 per U to $600 or $700 for a full rack.
Bandwidth pricing can vary in the same way. Usaul the more you commit to the
better your price. $30 Mbps-$150 Mbps.
Hope this helps a little