What's needed are first-level adventures. L1 characters need low-level adventures if they hope to get anywhere.
Perhaps there could be two parts to the Tomb adventure? The standard crawl of the adventure as planned, and something small for the first level tagalongs--essentially henchmen.
We could perhaps act as henchmen, or we could maintain a base camp in "safety," giving the higher-level PCs a staging area to adventure from.