Sorry for the long post but I am trying to make things simple! So - can I have a bit of help please?

For background:
We usually rack up about 2000-2500 TP each year through normal flying.
By Oct will be at 1900 and decided to do a quick TP run to get 600 to get GUF2 voucher (and for fun!)
Membership year is 8 Jan.
Have decided in 2016 to go for 5000TP - more for a laugh than anything else...I know people on this forum will understand what my colleagues think is utter madness!
I now how to use ITA matrix and I pay for KVS.
I am a bit confused about how to get the prices on AA.com but can always call a TA to book for me.
I get quite a bit of annual leave which is very flexible so I don't need to do OSL-HNL in one weekend!

So, now for the help bit:
1. Any ideas for a 600 TP run before Jan - was thinking maybe very simple like OSL to Puerto Vallerta?
2. Next Jan, I have got to be in Denver for a week so was maybe going to do HEL-HNL but stop in LAX (can you do that - one of the cheap fare bases said no stopover?) and just go LAX-DEN on a separate ticket. Would that be a good start towards the 5000?
3. This is the bit that really confuses me so I apologise: If I did HEL-HNL, is is possible to add in, for example LAX-MIA-LAX, on the same ticket (I suspect not as I am backtracking??) or do I go to HNL, stay a few days and within that few days buy a separate ticket to maybe go HNL-MIA-HNL (for example)?

I would be really grateful for any help - I have found this forum invaluable over the years so thank you!