Are you building a house or putting in a mobile home park?

I’m looking at purchasing an old single family house on a 25x100 property with 25’ of frontage on Summit Ave. in Jersey City’s Heights neighborhood.

Does anyone have experience in buying houses from online auctions? 

more than likely you will need to speak to the land groups of home builders or the land and development groups of multifamily buying groups and most are going to be publicly traded. make sure you have enough housing units. if you provide more info I can help out. there's a million different niches in development and more than likely less than 10 buyers for what you are talking about in any niche. we just reached out to Greystar for apartment development site we are putting together that is a vertical development. we called their office for the midwest and messaged every single person on their team on linkedin. put the effort in and you'll get results. 

In the house that I hope to rent out to mid-term travelers there is a treadmill and I am thinking whether to keep it there. 

Why would you borrow money against House A and use it as a downpayment for House B?

Plus the house hack... love to see it.

I house hack and so I self-manage.

Also look at how much the house has increased in price-if it has increased a lot, you may want to sell it to avoid paying capital gains which will kick in if you sell it a few years down the road.

I am currently house hacking and have a few tenants/roommates living with me.