I have the funds for a 3-4 month long VA cold calling campaign.

Same goes for needing a massive brand and marketing campaign.

I am going to start a marketing campaign sending letters to potential sellers indicating that I would be interested in buying their home. 

It also, to a greater extent than many other types of REI, requires well thought out and highly scrutinized marketing campaigns.

Try mailing campaigns.5.

We would also run a text campaign, some SEO and some targeted mail.

I work in sales in my W2 so pretty well versed in how to build sequences, outreach campaigns, scripts, etc. 

We send out emails, newsletters, campaigns etc. through the entire thing.

One option - (looks like you've already taken this route) - Shack up with a local investor-minded realtor, they will be more than happy to set you up on a specific, filtered investment property drip campaign. 

However, I'd like to think I have several "sticks in the fire" to find deals including: MLS, commercial brokers like CBRE and Marcus and Millichap, boutique brokerages houses, off-market campaigns via email or direct mail, wholesalers, turn key operators, etc..