Lot of grey area in travel for investment property a lot of condition "if's" as to the content of travel. Especially when the primary purpose was a vacation.

If you are traveling to explore a specific investment opportunity and you make the investment, your travel expenses are not deductible; they are added to the basis of the investment.

The  IRS auditors closely scrutinize deductions for overnight travel -- and many taxpayers get caught claiming these deductions without proper records to back them up.

Travel expenses are one of the IRS most scrutinized areas , might want to read the IRS publication 

Publication 463 (2016), Travel, Entertainment, Gift, and Car Expenses 

http://www.irs.gov/publications/p463/index.html