Was the three day journey mentioned in Numbers 10:33 the three day journey mentioned by Moses in Exodus?
First, let's look at the accounts in Exodus. Specifically, in Exodus 3:18, God directs Moses to tell Pharaoh that they will be going on a three-day journey to sacrifice. As a previous answer to a similar question mentions, this "three-day journey" was to test Pharaoh. So we could say that the "three" was an arbitrary number in this particular case.
Now, let's look at the account in Numbers 10:33. Here, the Israelites had already reached the "mount of the Lord". This verse points that "they departed from the mount". So now the Israelites are moving away from the mount "to search out a resting place for them."
Care must be taken when interpreting scripture. Just because two passages use the same word or number does not automatically mean they are referencing the same thing. The best way to start is by looking at the context of the verses in question and seeing if they have any ties to each other.