There's no big problem with Gib. It's controlled airspace, I think you still have to do an SRA to go in, but as you're in VMC (aren't you?) it's no problem, just follow the headings and altitudes given. It's to steer you away from the Spanish Prohited Area.
The Spanish are serious about you not flying there from Spain. Portugal or even Tanger (Morocco) will do fine.
Expect relatively expensive charges (landing/parking fees, passenger tax, apron charges) all paid in different places behind locked doors with no-one to open them. Cost me and my C150 £50 4 years ago.
Cigarettes are very cheap, but no tax discount on fuel.(Get fuel from Tanger). Refueller was totally incompetent when I was here, ended up with tidal wave of fuel over the a/c and ground which they then tried to charge me for. Refusal led to slanging match and refusal to fill up the other tank till I'd paid. A/c had to be washed down by fire department. It was a disgrace.
ATC were friendly and used to helping out when things got complicated.