The first thing that breaks is collections, and it breaks before anyone moves. On a park at $265 you're generally looking at residents with thin margins, so a $160 increase converts on-time payers into partial payers and partial payers into a legal process. Your model has one collection rate for all 24 months. Ask what it is. If it's 98 percent through a 60 percent increase, that single assumption carries most of the projected NOI.
The second failure mode is abandonment. A resident in a 1970s or 1980s single-wide with little resale value can hand you the keys, and in most states you can't simply take title and resell. There's a statutory abandonment or lien process, it takes time, and the timeline and requirements vary by state. Meanwhile the pad produces nothing, and if the home has to go, removal and disposal is real money, commonly a few thousand dollars per home and more where old flooring or siding needs special handling.
Third, that $425 comparable. Check what the comp parks have that this one doesn't. Paved roads, city water and sewer, working street lights and a manager on site all show up in market rent. If the subject has gravel and a private system, part of the gap is a capital budget rather than a pricing opportunity, and residents paying $425 will say so loudly.
What I'd add that isn't in your post: rent stabilization for manufactured housing exists at state and local level in a number of places, and a large increase is exactly what triggers a local ordinance campaign. Some states also give resident associations notice or purchase rights on sale. Both depend on the specific jurisdiction, and a local attorney is the only reliable source on which apply.
Also, your lender will size debt on collected in-place rent, not the pro forma.