Best place to train, depends what you're looking to get out of your combat training. Just fast combat EXP? Farming loot at the same time? Do you want to click train for quicker XP? All those things you need to consider. There's not a whole great deal you can farm for decent loot anyway at your level, except Green Dragons in wild (37 wild or castle). But once you get a higher combat, there's a lot you could do out of wild. Good safe spots to train for solely good combat EXP, be it AFK or click training are probably... The Witches House NPC's, lvl 48 hobs in Ardy? Jungle Spiders? I could be wrong. I don't train out of wild.
Best place to train in wild... Pretty sure it's Axes for combat XP, however, Pirates, Graveyard are also very good. If you're looking to make money on your main account while you train, perhaps farm the green dragons. Anything else currently in wild with good loot would be a bit to strong for a 88 probs.
Money making methods all depend on your personal situation really. What are your goals? Are you on PC or Android? If you can run more than 1 client, I would recommend it. Train combat on your main with the overall goal of being able to farm better mosters etc, whilst you perhaps collect herbs with a noobier account, to sell for 1k each. That's a great way to get started. Fishing is also an reliable money making method, Swordfish and Sharks are worth around 600gp each. Lobsters not so much but you can't get to swordies without lobs! There's tons of ways to make money. Flax (250gp each ish) and Bowstrings (300gp to 500gp ish) are highly sought after currently. Same with secondary supplies for Herblaw, all very highly sought after. Items needed for quests are commonly sold overpriced in the auction house, saving questers time and making newbs easy money.
Sorry if this is a wall of text, hopefully something in there will benefit you even if the rest doesn't. Welcome back to Rev and good luck on ur adventure