Firstly, don't worry too much about the occasional T3 timeout, even though they are marked as 'critical' in the log.
Secondly, you need to separate the problems associated with the two connections the SH establishes; The external DOCSIS cable side and the internal LAN side.
Looks like you may have problems on both. The post RS errors on your Acquired Downstream Channel indicate a slight problem with the DOCSIS side.
The inability for your wireless devices to get an internal IP address seems to show a problem with signal levels on WiFi.
Regarding the orange power light, this may well be normal. Can you quantify how hot the modem gets - they do run warm.
Now to some diagnosis.
The best way to diagnose issues on the DOCSIS side it to connect a device via an Ethernet cable directly to the modem and run some speed test like that.
Also check if you still have a connection via that route when other wireless devices fail.
Separate to that, you may have seen a diagnostic tool that's available from www.thinkbroadband.com. Known as a Broadband Quality Monitor (BQM) this is a free services that actively pings your connection every second. It can show up many kinds of faults on the Internet side.
On the WiFi side, there are some good scanning apps you can get that display signal strength and channels in use. This can help in selecting the best channels to use.
Whilst you could get reasonable WiFi coverage with the SH, many people bite the bullet and spend a bit of cash on their own WiFi systems that work with the SH (or indeed any other providers router).
There are many options if you go down that route including my solution of multiple Ethernet connected Wireless Access Points (WAPs or just APs)
