If there are problems, they must be pointed out, but they will not make up the whole report. In my experience, the pluses and the minuses tend to balance one another out. Please don't clean and tidy excessively beforehand. For example, if you normally have a shelving backlog, don't make a special effort to clear it before the site visit. No set of problems is unique to any one institution and you're doing your best with what you have, just like everyone else.
Environmental monitoring is an important part of preservation.
If there are environmental records available for the conservator, to study they may be able to draw some informed conclusions about the site conditions. The CNSA purchased some dataloggers last year to help members with environmental monitoring and any site preparing for an assessment has priority in borrowing one of these units. They are small and compact and require no work on the part of the user. The longer period of time recorded, the better. Seasonal changes such as winter to summer or fall to winter are best.