I started off my tour this summer with a bottle of Nashbar Dry Chain Lube (poured into a much smaller bottle) but ditched it within a week of the tour. I opted instead to stop at bicycle shops along my route and have it oiled every three to four weeks. I was never charged for the service and never felt like i needed the oil out in the "field" so to speak. The chain was new when I left in May and still doing good after 5,600 miles.
If you're route takes you past a lot of bicycle shops I would consider this.