Dear [Friend's Name],
Thank you for your letter! I'm glad to hear from you. To answer your questions: first, I’ve been doing well, just keeping busy with schoolwork. Second, I recently started a new book that I’m really enjoying; it's quite a page-turner! Lastly, I would love to catch up soon; how about we meet this weekend? Let me know what time works for you.
Looking forward to hearing back from you!
Best,
[Your Name]