I'm fairly comfortable now with Audio input and editing but this whole midi part of Sonar is very complicated at first glance.
I don't have a midi input device so I thought I'd try by mouse until I see if it's worth the trouble.
I see an amazing and confusing pile of devices included.
Step Sequencer
Software synths
Beatscape
Studio Instruments
Drop Zone
Dimension Pro
Rapture
Session Drummer3
Etc
Where should I start for basics via the mouse for input. 
Say for drums to start and then, once I'm comfortable, maybe bass then, once I get a keyboard eventually some strings?

Start with TUTORIAL 4 in the X1 Reference Guide.
You might also want to checkout http://www.cakewalk.com/C...NARU.aspx/Master-Class for Drum Production videos.

Great lead thanks

Use Session Drummer to create a drum track. All you have to do is load up a program, select a pattern and then drag the pattern to a MIDI track. Easy. 

Ok thanks, I'm going to give that a try today.
I'll look for some session drummer videos first.

So would you recommend using SD3 for drums and then some other program for bass? (again, no input keyboard, just mouse)
I can see how other for instruments it would be better to have a keyboard for input.

If you are going to do much MIDI you really need to pick up some type of input device other than a PC keyboard/mouse, usually a keyboard. As for a synth, from the stuff supplied with SONAR, you might want to start with DimPro (esp. expansion pack 3) or the SI-Bass Guitar. But if you play guitar, you might as well pick up a bass rather than relying on a synth for bass.

So would you recommend using SD3 for drums and then some other program for bass?

Yes, because Session Drummer only does drums. You can use TTS-1 or the SI-Bass program or any number of other softsynths (Pentagon, Z3TA+, Dim Pro, etc.) depending on what type of bass sound you want. There are many to choose from. 

+1 for Dim Pro on the bass.

There's lots of very usable patches included

Also, don't overlook the Pentagon - it's just a shame there's no better patch management - you'll find Bass patches scattered across many banks!

Thanks guys.
I guess I'm hedging my bets, not wanting to buy a bunch of gear I'll not use if I don't find the MIDI thing useful.
I don't mind studying and I don't mind paying for gear but I hate to waste either one.