The quality of your tenant is just as important as the investment you make.  

My personally favorite spot so far is Ko Olina but I'm open minded.

Do you have a personal connection to either of those cities/markets?

Personally I am thinking 1c.

I personally would go that route as it would probably be less expensive. 

-----------------------------------------------------------------------------------------------------------Recommend you first figure out the property Class you want to invest in, THEN figure out the corresponding location to invest in.Property Class will typically dictate the Class of tenant you get, which greatly IMPACTS rental income stability and property maintenance/damage by tenants.If you apply Class A assumptions to a Class B or C purchase, your expectations won’t be met and it may be a financial disaster.If you buy/renovate a property in Class D area to Class A standards, what quality of tenant will you get?

You'll get differing amounts and qualities of leads depending on the type of marketing, but also depending on who you're marketing to and where.

Regardless, you might find the copy & paste info below helpful:)--------------------------------------------------------------------------------------------------Recommend you first figure out the property Class you want to invest in, THEN figure out the corresponding location to invest in.Property Class will typically dictate the Class of tenant you get, which greatly IMPACTS rental income stability and property maintenance/damage by tenants.If you apply Class A assumptions to a Class B or C purchase, your expectations won’t be met and it may be a financial disaster.If you buy/renovate a property in Class D area to Class A standards, what quality of tenant will you get?

You will quickly find, as you generate local person-to-person relationships, how many opportunities open up! 

I personally used Jon McGraw in the past and he is extremely knowledgeable in the field.