I actually have not used oak for a bed before, so take my advice with a grain of salt because there may be an aspect I'm missing.
Since it is a kit, I assume it is at least rough finished. That being the case, I would use something around 220 grit sandpaper to do the final sanding. After sanding and staining, I recommend using mineral spirits to clean the wood of excess dust/stain
Last summer I built a redwood fence (using both rough cut and finely sanded tongue and groove) and used SuperDeck Semi-Transparent Stain and Sealer. It is a deep penetrating stain and sealer all in one. Works very well and I never needed to apply a second coat. I used the same stuff on a redwood gate, and I didn't refinish it for several years and it really didn't need it, I just did it because I was building the fence and wanted them to match. I live in a desert valley where the gate and fence get beat with 90-115 degrees for half of the year, dust, wind and around 30 degrees in the winter, so the stain holds up very well by any standard.
SuperDeck Products Hope this helps.
- Daniel
