Where/how to start?

I am not sure about the Node model number.  Its the basic unit with no disk storage.  I am purdy sure the Node is Wifi capable so you can start with just setting up the node on you existing network.   If that is flakey and you are getting drops then you can augment your network.  Many people on this forum have success with extenders and wal warts but I personally think that technology sucks.  At least it has for me and people I know.   I would suggest exploring going to a mesh network topology.  Little extra $$ but worth it if you are going to stream, easy setup as well. Have one of the network-nodes at your rig and hardwire ethernet to the Blue Sound-Node. 

The Cambridge unit is also nice but its double the $$.   But also a good choice. 

Test the waters with the Node.  If streaming is for you (hooked on the crack pipe)  then you can start to explore whether you want separates or all in one streamer/DAC from high end manufactures like Bryston, Lumin and Moon.

Another option for 'testing the waters' on a budget using the DAC in your Oppo is the iFi Zen stream. $400. A streamer only, no internal DAC. 

Thanks for the recommendation of iFi Zen. This is also new to me.

Can somebody comment on Node's DAC? Would it be better than the DAC on Oppo? If Oppo's DAC is better I will go for iFi Zen. If Node's DAC is better, I would go for Node. Well, if they are about the same I will go for the one that is easier and more flexible to use.

That would be my start even though I may spend more later on better streaming device + DAC. I don't know too much about networking issue. Once I gain more knowledge I will take a look on better network setup.

Thanks again.

OP… “Then, I can use a wall wart WiFi extender?”

Yes. I have a $100K+ system streaming off a $59 NETGEAR wall wart. Simple and cheap.

I would recommend investing in a high quality standalone DAC which would greatly improve the SQ of any digital system. I have a Denafrips Pontus II DAC and use it with both my Bluesound Node 2i and Audiolab CDT 6000 transport.  Denafrips DACS are extremely popular and there are numerous reviews available and postings on this forum.  Good luck with your digital quest!