Hi Dan,
Seemingly healthy people being blind-sided by a seizure followed by a brain tumor diagnosis is, unfortunately, a fairly common theme here. When I related a similar story to my neurosurgeon, he shrugged and said in his thick Swiss accent, “Thees ees brain tumor.” The good thing is that the tumors that cause seizures are often discovered while they are still low-grade.
I don’t blame you for being afraid of having another seizure, but don’t worry about your co-workers. Sometimes people don’t know how to react, but if you can educate some of your co-workers about what a seizure is (basically an electrical storm in your brain) and what to do* in case you have another, it should help everyone feel less freaked out.
Hopefully the Keppra will work for you; it’s one of the most commonly used anti-epileptic drugs, especially for tumor patients. 2,000mg/day is a fairly high dosage so you might have some side-effects, but they often go away or lessen after a couple of weeks. I’m on 1500mg/day and the only side-effect I have is sleepiness. Some have mood swings, irritability, depression, even “Kepprage”, but again, these usually lessen with time, but be sure to tell your doctor ASAP if you experience severe depression. Never quit Keppra suddenly, that in itself can cause seizures.
As for not feeling right, that’s understandable after what you’ve gone through. However, it could be the Keppra; it could even be the Keppra doing its job. I don’t know exactly what you mean by “not right”, but many people with epilepsy, tumor or not, experience auras which often precede seizures or are small seizures in themselves. These auras can take many forms, but many people report feeling like they are on the verge of having a seizure, but that the medication (this happens with other anti-epileptic meds too) is blocking the full seizure.
Another thing that may not feel right is mental focus. Most, if not all anti-epileptic meds work by dampening the electrical activity in the brain. That doesn’t mean that your thinking will be less clear or slower, it just means that you may need to focus more to do the same tasks you normally do. If I’m trying to do anything with math like simply adding up the bills while someone is talking, I have to ask them to be quiet. But then I’ve never been that great at math:/
The trip sounds great! You should still be able to enjoy everything as before, maybe more so after what you’ve been through. But, definitely be careful with alcohol. Some people are able to drink the occasional beer or glass of wine once they have their seizures under control, but alcohol lowers your seizure threshold so it’s tricky. Definitely talk to your doctor about it.
Talk about rambling

Hope you found something useful in it.
Hope all goes well with your doctor on Monday. Let us know what you find out.
PS
*Basic seizure first aid
DON’T put anything in the mouth. It’s a myth that you can choke on your own tongue
If possible, turn the person on his/her side so that if they vomit they don’t choke on vomit.
Place something soft under the head.
Clear area of anything that might fall on or harm seizure patient.
Time seizure, if seizure lasts more than 5 minutes, or if there are multiple seizures in a row, call 911.