Appreciate everyones input. Figured I'd provide an update for those interested:

1. Flying (a less than ideal but not horrible flight plan) from IAD > MUC > ATH. Both are on Lufthansa. Return flight will be ATH > MUC > IAD. One operated by Air China and one by Lufthansa. I Booked the flights on United.com. So I used the 72,000 United MileagePlus award miles and transferred 48,000 Chase Ultimate Rewards points. Total United points was 120,000 for our airline tickets.

2. Spending 1st night in Athens at Hotel Grande Bretagne. Reserved with 10,000 SPG starpoints + $180. Will likely cancel later and re-book fully with Chase UR points.

3. Flying to Crete (HER) from ATH on Aegean. Booked directly for a total of $215. Will likely cancel it later and book fully with Chase UR points.

4. Spending 5 nights in Crete at the Blue Palace, on 90,000 SPG starpoints and enjoying the 5th night free. Still need to decide best way to rent a car while there.

5. Ferry to Santorini. Still need to figure out how to best book that.

6. Spending 4 nights in Santorini but haven't decide where (Oia or Imerovigli). Want to book fully with Chase UR points.

7. Ferry to Athens. Still need to figure out how to best book that.

8. Spending last night in Athens, likely at Hilton using 75,000 HHonors points.

Current Remaining point count:
-0 United MileagePlus award miles
-3,000 SPG Starpoints
-0 (likely) Hilton HHonors points
-212,000 Chase Ultimate Rewards
-93,200 Amex Membership Rewards points

Any more feedback or suggestions?

Thanks!