Generally, to keep potatoes from being soft start with a high solids (starch) potato such as an Idaho Russet Burbank variety.  I’d order a smaller size, such as a carton of 100 or 120 count if you want each chunk to have some skin on it.  For a nice golden color I like to use a mixture of 50/50 olive oil and butter that has been melted.  Oven bake, single level, on sheet pans.  Sometimes I add a little dried paprika or even turmeric to get a nice contrast of color.  I think you could cook until fork tender, about 185° F, but you’ll have to experiment with the times.  Usually they are done if placed on a room temp pan at 425° F for about 25-45 minutes, depends on the size of the cuts (chunks take less time than wedges).

Here is a video that may be of help if you do wedges.

If serving right afterwards, just place into a heat cabinet or hot box until needed. Transporting makes it a little harder to keep crisp.  Can you cool and re-heat at the event?  If not, place into steam table inserts and at the other end use chafing dishes and portable heat to keep warm.