We will deal with both halachic and educational issues, starting with the former.
The institution to read the Torah, both on Shabbat and during the week, is an ancient and beloved one initiated by Moshe.[1] There are, though, ample sources in halacha from which it follows that an individual may travel even though it will cause him to miss kr’iat haTorah. The Shulchan Aruch, for example, describes the circumstances under which one may embark before Shabbat, for non-mitzva purposes, on a voyage by boat that will compromise his ability to properly keep Shabbat.[2] The poskim do not raise the issue of kr’iat haTorah, and it is not plausible to think that they assumed that a sefer Torah would be available. It seems likely then that missing kr’iat haTorah is not sufficiently problematic to warrant avoiding travel. There is also discussion about traveling for non-mitzva purposes in a way that makes one miss a minyan.[3]
In one way, at least, there may be a leniency regarding kr’iat haTorah. The mishna[4] lists those matters for which a minyan is required. Kri’at haTorah is included; megilla[5] reading is not. The Ramban[6] explains by noting that the matters listed in that mishna are obligations of only the tzibbur (community). Reading the megilla, in contrast, is also an obligation of the individual. If kri’at haTorah is indeed not an obligation of the individual (not everyone agrees[7]), then it is not critical that an individual who was forced to miss kri’at haTorah find a minyan to make it up.[8]
The question, though, is how to define a tzibbur. If your minyan of campers is a tzibbur, then it bears the full weight of the obligation. (Great need might outweigh this duty, but the question is still pertinent.) The Yabia Omer[9] cites stories of talmidei chachamim who had minyanim in their homes without a sefer Torah and understands that the responsibility of kri’at haTorah was met by the tzibbur in the town’s shuls. In your case, the requirement could be satisfied by the rest of the campers, who remain behind. It appears logical that the traveling group does not become a tzibbur until it begins to daven. However, that occurs when a sefer Torah is unavailable, and, at that point, they lack the means to carry out the obligation. It is permissible to leave camp and thus create a situation where you will be unable to read the Torah, if you do so at a time when the obligation to read has not begun.
For educational reasons, even beyond halachic requirements, one should consider various options to make kri’at haTorah a possibility. For example, getting access to a sefer Torah at Mincha time is a halachic possibility,[10] especially for Ashkenazim.[11] (Besides technical concerns, it is problematic to have a sefer Torah travel with the group.[12]) The educational message of making an extra effort not to forgo kri’at haTorah can have a positive impact on your campers. Even if you are unable to arrange it, it is educational to let them know how hard you tried and to, perhaps, discuss the issue with them. Many of your campers are from backgrounds where they do not make it to shul every morning. A conversation in which you express how hard it was for you to miss kri’at haTorah even once is likely to be much more effective than preaching or punishing when they miss davening.