Hi everybody! I have to admit that I have been lurking for quite some time and figured it was about time to say hello (and get some advice!!)

Here's my story:
I'm traveling with my husband, 9 year old daughter, and mother. We will be arriving in Barcelona a couple days before the cruise departs to explore the city as much as possible (staying at AC Diplomat through Disney). We are doing Disney excursions in all ports except Corsica where we plan to just walk around a bit and check things out. We are all very excited to be cruising with Disney again and to be going to Europe!!
I was hoping to get some of your expert advice!! I have been reading the boards and books and what not, but still pondering a few things:
1. What to wear: Not on the ship, of course, but in the ports; especially while in Barcelona "on our own". I've gotten myself all worked up about wearing the right things so we don't look too much like tourists dying to be taken advantage of. I know I am overthinking the whole thing, but can't help myself. Seems like shorts aren't common, but am worried about being hot in capris with the summer heat! Thinking of sundresses, but most of mine are sleeveless, so then I have to carry around a sweater for entering churches... I'm being silly, right? Anyway, I would love to get some ideas on what people are planning to wear!
2. How much money to bring: I know it's really a personal thing, but just looking for any ideas! Plan to charge wherever we can so don't have to worry about having too much cash on hand. What do I need to have cash for? Not much I think... Just for a little drinks or snacks in between meals, right? Ooh, and for the bathrooms sometimes. Maybe some for cab fare in case we take a taxi in Barcelona... Anything else?
3. Speaking of cash: should I just exchange at Barcelona airport when I get there? Or should I try to exchange beforehand? Also, if I need more after Barcelona, did I read somewhere you can exchange on boards, but have to have cash (as opposed to charge to room)?
4. Barcelona: What are people doing who are arriving early (or staying afterwards)? I was looking at the Hop on Hop Off bus. Does anyone have any experience using this? Is it easy to recognize (bus stops)? Do you know anything about getting tickets?
Okay, I am sure I have a thousand more questions, but I feel bad enough pumping you guys for this much information

So, thank you already for all the helpful information that has been posted and in advance for attempting to answer some of my questions