Brutus completes his second week of training and begins working on selling the spell books at the best possible price.
Since the rest of the party departed, there has been no word from them. A small group was dispatched to the caves after five days of silence but they found very few signs of them, and nothing recent - it was almost as if they'd evaporated into the air.
Tracks were found of them entering, but none, at least none since the first unsuccessful foray, were found of them leaving.

In the down time, Brutus will also investigate the carpet. Thoroughly. With a magnifying glass. He has time.

Brutus finds nothing special about the carpet the Identify spell didn't show. If there are any secrets to be found, they're beyond his skill.

Even if he hires a sage to help him?

Cost, 500gp?

A sage specialising in...?

Ancient carpets, Tapestries, etc.

What do we already know of it?

That would require a little trip to the city.
So far you know it can shrink down to about the size of a handkerchief and back up again - that's it. Useful for lining the bottom of your tent with, but otherwise a bit pointless.

I am sure those big uglies did not carry it around to line their tents, so more research needed. How far away was a bigger city?

Newford, about a hundred miles by road.
Take a look at the map thread.

Saw that. But in days travel?

Depends on how you're travelling. Horseback is obviously quicker than foot, but there's a fair bit of mountainous terrain in the 1st third of the journey which would slow progress. Check the WSG for travel times, etc - 3 months is a long time to work with, but as NOBODY had a clue the party would be gone that long, I'm sure Brutus would have wanted to minimise time away as much as possible.