@Richard Rinehart  both markets have lower purchase prices compared to the other popular cash flow markets.  

Has anyone noticed any differentiating factors between some of the more popular solo401k providers that frequent BP other than price?

Your time here will be well spent.Your profile is empty and there is no mention of a specific REI area of interest, so, I added the below links from three of the most popular niches for your selection of one or all.https://www.biggerpockets.com/renewsblog/2015/01/31/ultimate-beginners-guide-real-estate-wholesaling-2/ (Ultimate beginners guide to wholesaling)http://www.biggerpockets.com/renewsblog/2014/01/07/flipping-houses/ (step by step guide to flips)http://www.biggerpockets.com/renewsblog/2013/02/22/buying-rental-property/ (how to buy a rental property)Now that you have made the move, below are some links that will help with the navigation of the site. http://www.biggerpockets.com/startherehttp://www.biggerpockets.com/meethttps://www.biggerpockets.com/alertsHow to Use @Mentions on BiggerPocketshttps://www.biggerpockets.com/ruleshttps://www.biggerpockets.com/termshttps://www.biggerpockets.com/inviteshttps://www.biggerpockets.com/perkshttps://www.biggerpockets.com/forums/categorieshttps://www.biggerpockets.com/courses/a-beginners-introduction-to-real-estate-investing (video courses)https://www.biggerpockets.com/real-estate-investing (Ultimate beginner's guide to REI)Before your 1st purchase, please ensure you visit the below link for some tips.https://www.biggerpockets.com/renewsblog/2014/12/19/real-estate-investing-success-smart-tips/REI books suggested by BPershttps://www.biggerpockets.com/renewsblog/2015/11/13/7-real-estate-books-beginner-investors/ (7 absolute must read books for beginner REIs)http://www.biggerpockets.com/renewsblog/2013/04/14/best-real-estate-books/?

This only applies to the District of Columbia.There is a sorta-kinda interesting comment discussion on a popular local blog called Prince of Petworth (PoP) regarding TOPA "From the Forum – Assigning TOPA Rights".

Since your question seems to be tailored to vacation rentals, I would look up what the most popular vacation destinations are and the demographics of who is most likely to rent a vacation home in that destination.    

Writing down your goal is important in achieving it and that's what you have done.Now, with that said since you are not familiar with the niches, I added three of the most popular ones for you to review and decide on one, focus on it like a laser and then expand your footprint to the others at a later time.Don't be afraid to revisit the forums to pose questions which you may/will have.https://www.biggerpockets.com/renewsblog/2015/01/31/ultimate-beginners-guide-real-estate-wholesaling-2/ (Ultimate beginners guide to wholesaling)http://www.biggerpockets.com/renewsblog/2014/01/07/flipping-houses/ (step by step guide to flips)http://www.biggerpockets.com/renewsblog/2013/02/22/buying-rental-property/ (how to buy a rental property)It doesn't matter if you are young or old, totally new or need to build upon your experience.Yes, you have just announced a commitment to the thousands in this community about your seriousness regarding REI and have taken this bold step to affirm it.Your time on this site with the BiggerPockets community will be well spent and can be financially rewarding if you so desire.Don't get overwhelmed by the massive amount of data archived on this site.Simply, bone up on the areas that you need to expand knowledge in such as, Forums, Marketplace, Learn, Network, Analyze and Resources.Feast on the Podcasts, #askbp Podcasts, blogs and webinars REI books suggested by BPershttps://www.biggerpockets.com/renewsblog/2015/11/13/7-real-estate-books-beginner-investors/ (7 absolute must read books for beginner REIs)http://www.biggerpockets.com/renewsblog/2013/04/14/best-real-estate-books/?

You also won't get section 8 or any other federally funded renters without a lead cert.Good luck with your hunting!

Ok, now that you have taken your initial step, below are some quick links to get engaged.Since no mention of a specific REI area of interest was stated, I added three links from the most popular niches for your review and selection of one or all.https://www.biggerpockets.com/renewsblog/2015/01/31/ultimate-beginners-guide-real-estate-wholesaling-2/ (Ultimate beginners guide to wholesaling)http://www.biggerpockets.com/renewsblog/2014/01/07/flipping-houses/ (step by step guide to flips)http://www.biggerpockets.com/renewsblog/2013/02/22/buying-rental-property/ (how to buy a rental property) http://www.biggerpockets.com/startherehttp://www.biggerpockets.com/meethttps://www.biggerpockets.com/alertsHow to Use @Mentions on BiggerPocketshttps://www.biggerpockets.com/ruleshttps://www.biggerpockets.com/termshttps://www.biggerpockets.com/inviteshttps://www.biggerpockets.com/perkshttps://www.biggerpockets.com/forums/categorieshttps://www.biggerpockets.com/courses/a-beginners-introduction-to-real-estate-investing (video courses)https://www.biggerpockets.com/real-estate-investing (Ultimate beginner's guide to REI)REI can be very daunting, but, before you go searching for that 1st buy, please take a few minutes to bone up on the tips in link below.https://www.biggerpockets.com/renewsblog/2014/12/19/real-estate-investing-success-smart-tips/REI books suggested by BPershttps://www.biggerpockets.com/renewsblog/2015/11/13/7-real-estate-books-beginner-investors/ (7 absolute must read books for beginner REI)http://www.biggerpockets.com/renewsblog/2013/04/14/best-real-estate-books/?

So for your example - if you want a $50k salary, only $40k would be subject to SE tax assuming a $10k premium. the full $50k would be subject to federal taxes, but then the owner deducts the $10k premiums on his/her 1040.Contributions based on salary of $50k.

Some popular events are NoteExpo and PaperSource 3.