That being said, what is the purpose of your LLC and would you feel more comfortable having an umbrella insurance policy to cover your liability instead? 

I use spearhead insurance,theyll do LLC's and stuff in your name. good prices on umbrella policies as well

Just get an umbrella insurance policy until you grow your portfolio large enough.

AS for asset protection depends on what type of assets you have to protect so on and so forth.Generally speaking on your personal resi good insurance and nice big umbrella will work 99% of the time.AS your estate grows for sure there are methods that will help you with Trusts being one of the better ones from what I have seenBut to do it properly is 15 to 50k and then you have yearly maintenance and such.. 

You should definitely get umbrella liability policy and you will need to change homeowners to cover rentals. 

Do you really need to purchase in a LLC or are there other avenues that get you as much protection (eg umbrella insurance, trusts) if you purchase in own name and then protect after?

You can get a personal liability umbrella rider from your auto insurer if your concern is liability.

@Geri May I'd recommend saving $ on the LLC and going with General Liability limit of $1M, and add an Umbrella policy if you feel you need higher limits.  

To protect myself, I have an umbrella policy versus the LLC. 

But once you have a net worth over a few hundred thousand buy an umbrella policy.