I this how you ask a question expecting the answer to be an adjective that takes the dative?
Centuriō nocte ad castra hostium modō agricolae ībat.
Cui modō Cenuriō nocte ad castra hostium ībat?
Modō agricolae centuriō nocte ad castra hostium ībat
Please give me a couple more (simple) examples. 
Thank you.
Jim
agricolae is not dative, but genitive: modus.
Esp. freq.: modo, in modum, or ad modum, with a gen. or adj., in the manner of, like: servorum modo, in the manner of, like slaves, Liv. 39, 26: pecorum modo trahi, Tac. A. 4, 25: in modum ramorum, Col. Arbor. 22:
Thank you Bedwere
Modō plus the genitive “servorum modo”, like slaves.
That helps a lot because elsewhere in this reading it was followed by the genitive (which I thought must have been a typo! LOL
But the dative is used with adjectives (and a few Adverbs) of fitness, nearness, likeness, service, inclination, and their opposites.
Accammodātus adapted to, aptus fitted to, amīcus friendly to, inimīcus, hostile to, infestus hostile to, invīsus hateful to, molestus troublesome to,
Stuitability: idōneus, opportūnus suitable to, ūtilis useful to, inūtilis, finitimus neighbouring to, proprius near to, vīcīnus near to, par equal to, similis, dissimilis, grata pleasing to, nōtus known to, ignōtus unknown etc
So that still leaves the original question
How do you ask a question when the answer includes an adjective that takes the dative.
Idōneus can go with a word in the dative to mean “suited for.”
Like this?
Cui idōneus est hic locus? For what is this place suited?
“Hic locus est idōneus castrīs. This place is suitable for a camp.
Cui idōneus est mons. For what is this mountain suited?
Hic mons est idōneus locus urbī. dative
This mountain is suitable for a city.
Cui erat fuga hostium grāta?
Grāta legiōnī erat fuga hostium.
Thank you
Jim