That assumes the house will appercaite at less than 2%/yr with they given inflation, at first guess seems low, but you are in the market so that could be wrong.

We have 100k in the bank and don’t want inflation to destroy it.

So now what that did by increasing the interest rate is you had fewer people buying homes and so now the supply of buyers started to decline and yet you had these artificially inflated values of homes that now you had less buyers.

I'm finding that in my market (WA), with the severe appreciation and resultant increase in property taxes, as well as increases in insurance, labor, material, and general inflation - you can go backwards VERY QUICKLY in cash flow on your properties if you aren't keeping a close tab on rental rate increases and making sure they happen. 

I would be careful about adjustible rate debt in general, because with inflation it's looking like they're on an upward trend, although still lowYou'll want to work with your CPA on setting this up & any tax questions regarding the interest payments, if they'd be debt service on the new propertyThe longer you need the money & the more money you need, the more likely a low fixed rate mortgage would be the better option, [between that and an adjustible home equity line of credit (heloc) if you're considering the 2 types]But some banks offer a loan within a line on their helocs - if you use a big portion of the line you can call them & fix the rate have a scheduled payment each month, which includes principal.  

Figure losing whatever the % number for inflation is until I put it to use.

Has inflation, increased gas prices, and overall travel expenses impacted your bookings or future bookings?

Can't predict the future but with interest rates running up as they are, and the feds saying they want to catch up to inflation, I'd say do it now. 

At this time of War and Inflation with a backwards Government, Stress Testing our whole Economy with unnessasary pressure on all Americans, do you want to be a Buyer? 

Her retirement funds should be sufficient, but... inflation.