accessibility is an issue. obviously, not just anyone (not even a college student) can just order a bottle of 2,5-dimethoxy-benzaldehyde.. I just recently decarboxylated some lab-grade tryptophan into tryptamine (gotta recrystallize it though); then I could theoretically proceed to DPT, via diisopropylamine, propyl iodide, and IPA. It appears rather straight-forward.
converting tryptophan to tryptamine isn't; neither is synthing DPT as long as you don't try to capitalize on it, no crime has been committed. nothing involved in its synthesis is illegal, but getting access to diisopropylamine is another story.