「Check in wasn't as smooth as we expected since there are no hotel staff on site during the off-season. Apparently I should have received a text with instructions on check in including the lock box code 24 hours before check in, but never got this.
A helpful long term guest at the property helped out by calling the property manager for me at around 8pm. Her passed along the info over the phone and it all worked out.
In the morning I chatted with another couple staying that had the same issue...