However, my grandparents are the ones who started it all and my father already had a lot of resources at his finger tips when he began.

Nothing against one man/woman operations but the reality is a single person performing property management flat doesn't have the resources to effectively manage many properties.

Please feel free to provide any tips or resources.

It is designed to assist a project manager in developing a plan, assigning resources to tasks, tracking progress, managing the budget, and analyzing workloads.

What are your favorite sites/resources for researching list prices, sale prices, cap rates, rents, employment and demographic trends, etc?

Do you have any good resources to learn about IRR?

Podcasts above are great resources. 

We have some money in our Heloc to either buy another investment property or just buy ourselves a house that does not need massive work, good neighborhood and is energy efficient.

Yes, the mobile homes built today are more energy efficient than their predecessors, but they can't beat the solid interior and exterior of a Tiny Home built by a professional company.

When I did this two months ago they knew nothing about the new Title 24 energy requirements (mainly 1.5-2kw PV solar mandate roughly $4k after fed tax credit) that go into effect January 1 nor the new assembly bills (SN 13 then as yet unsigned).